diff --git a/src/coremods/core_message.rs b/src/coremods/core_message.rs
index 1b3b23f..854f69a 100644
--- a/src/coremods/core_message.rs
+++ b/src/coremods/core_message.rs
@@ -599,7 +599,8 @@ pub(crate) fn deliver(s: &mut Server, uid: Uid, params: &[String], notice: bool)
         }
         // SILENCE: if the recipient silenced the sender, drop it silently — the
         // sender is never told (that's the point), but still gets their own echo.
-        let silenced = s.is_silenced(tuid, &prefix);
+        // SIGNORE is mutual: drop if either party server-ignores the other.
+        let silenced = s.is_silenced(tuid, &prefix) || s.signore_blocks(uid, tuid);
         let pm = format!(":{prefix} {cmd} {target} :{text}");
         let ctags = s.line_ctags.clone();
         let msgid = s.next_msgid();
diff --git a/src/coremods/core_watch.rs b/src/coremods/core_watch.rs
index a849570..6bf96be 100644
--- a/src/coremods/core_watch.rs
+++ b/src/coremods/core_watch.rs
@@ -14,6 +14,7 @@ pub fn commands() -> Vec<Box<dyn Command>> {
         Box::new(Watch),
         Box::new(Monitor),
         Box::new(Silence),
+        Box::new(Signore),
         Box::new(Accept),
     ]
 }
@@ -298,6 +299,77 @@ impl Command for Silence {
     }
 }
 
+// --- SIGNORE (personal mutual server-side ignore) ---------------------------
+
+fn signore_list(s: &Server, uid: Uid) {
+    let (nick, list) = s
+        .users
+        .get(&uid)
+        .map(|u| (u.nick.clone(), u.signore.clone()))
+        .unwrap_or_default();
+    let sn = &s.name;
+    if list.is_empty() {
+        s.send(uid, format!(":{sn} NOTICE {nick} :Your SIGNORE list is empty."));
+    } else {
+        for m in &list {
+            s.send(uid, format!(":{sn} NOTICE {nick} :SIGNORE {m}"));
+        }
+    }
+    s.send(uid, format!(":{sn} NOTICE {nick} :End of SIGNORE list."));
+}
+
+/// SIGNORE — a personal, mutual server-side ignore. `SIGNORE <mask>` (or `+mask`)
+/// blocks a user both ways: neither of you sees the other's channel or private
+/// messages. `SIGNORE -<mask>` lifts it; a bare `SIGNORE` lists your masks. A bare
+/// nick becomes `nick!*@*`.
+struct Signore;
+impl Command for Signore {
+    fn name(&self) -> &'static str {
+        "SIGNORE"
+    }
+    fn handle(&self, s: &mut Server, uid: Uid, params: &[String]) -> CmdResult {
+        let Some(arg) = params.first() else {
+            signore_list(s, uid);
+            return CmdResult::Ok;
+        };
+        let nick = s.users.get(&uid).map(|u| u.nick.clone()).unwrap_or_default();
+        let sn = s.name.clone();
+        let (add, raw) = match arg.strip_prefix('-') {
+            Some(m) => (false, m),
+            None => (true, arg.strip_prefix('+').unwrap_or(arg)),
+        };
+        if raw.is_empty() {
+            signore_list(s, uid);
+            return CmdResult::Ok;
+        }
+        let mask = normalize_mask(raw);
+        if add {
+            let max = s.conf_num("maxsignore", 64usize);
+            let full = s
+                .users
+                .get(&uid)
+                .map(|u| u.signore.len() >= max && !u.signore.contains(&mask))
+                .unwrap_or(true);
+            if full {
+                s.send(uid, format!(":{sn} NOTICE {nick} :Your SIGNORE list is full ({max} max)."));
+                return CmdResult::Fail;
+            }
+            if let Some(u) = s.users.get_mut(&uid) {
+                if !u.signore.contains(&mask) {
+                    u.signore.push(mask.clone());
+                }
+            }
+            s.send(uid, format!(":{sn} NOTICE {nick} :SIGNORE \x02{mask}\x02 added — you and they can no longer see each other's messages."));
+        } else {
+            if let Some(u) = s.users.get_mut(&uid) {
+                u.signore.retain(|x| x != &mask);
+            }
+            s.send(uid, format!(":{sn} NOTICE {nick} :SIGNORE \x02{mask}\x02 removed."));
+        }
+        CmdResult::Ok
+    }
+}
+
 // --- ACCEPT (callerid +g allow-list) ----------------------------------------
 
 fn accept_list(s: &Server, uid: Uid) {
diff --git a/src/server.rs b/src/server.rs
index fb3f39d..fbb4fa8 100644
--- a/src/server.rs
+++ b/src/server.rs
@@ -390,6 +390,7 @@ impl Server {
                 watch: Vec::new(),
                 monitor: Vec::new(),
                 silence: Vec::new(),
+                signore: Vec::new(),
                 accept: Vec::new(),
                 quitting: None,
                 flags: UserFlags::default(),
@@ -1200,6 +1201,10 @@ impl Server {
         let members: Vec<Uid> = ch.members.keys().copied().collect();
         let time_tag = format!("time={}", iso_time(now()));
         let account = self.users.get(&src).and_then(|su| su.account.clone());
+        // SIGNORE (mutual server-ignore): the sender's mask + list, hoisted once.
+        let src_mask = self.users.get(&src).map(|su| su.prefix()).unwrap_or_default();
+        let src_signore: Vec<String> =
+            self.users.get(&src).map(|su| su.signore.clone()).unwrap_or_default();
         // one cached line per (server_time, account_tag, message_tags) combination
         let mut cache: [Option<std::sync::Arc<str>>; 8] = std::array::from_fn(|_| None);
         for m in members {
@@ -1212,6 +1217,13 @@ impl Server {
             if u.flags.deaf {
                 continue;
             }
+            // SIGNORE: skip a member mutually server-ignored with the sender
+            if (!src_signore.is_empty() || !u.signore.is_empty())
+                && (src_signore.iter().any(|p| crate::channels::glob_match(p, &u.prefix()))
+                    || u.signore.iter().any(|p| crate::channels::glob_match(p, &src_mask)))
+            {
+                continue;
+            }
             if op_only && self.rank(m, key) < crate::channels::RANK_HALFOP {
                 continue;
             }
@@ -1507,6 +1519,7 @@ mod tests {
                 watch: Vec::new(),
                 monitor: Vec::new(),
                 silence: Vec::new(),
+                signore: Vec::new(),
                 accept: Vec::new(),
                 quitting: None,
                 flags: UserFlags::default(),
diff --git a/src/users.rs b/src/users.rs
index cf957dd..ae95865 100644
--- a/src/users.rs
+++ b/src/users.rs
@@ -252,6 +252,7 @@ pub struct User {
     pub watch: Vec<String>,    // WATCH list — lowercased nicks
     pub monitor: Vec<String>,  // MONITOR list — lowercased nicks
     pub silence: Vec<String>,  // SILENCE masks — nick!user@host globs
+    pub signore: Vec<String>,  // SIGNORE masks — mutual server-side ignore (both ways)
     pub accept: Vec<String>,   // ACCEPT list — lowercased nicks (callerid +g)
     pub quitting: Option<String>, // set by QUIT; drained by the core
     pub flags: UserFlags,
diff --git a/src/watch.rs b/src/watch.rs
index 935fdd1..7cf6512 100644
--- a/src/watch.rs
+++ b/src/watch.rs
@@ -208,4 +208,23 @@ impl Server {
             .map(|u| u.silence.iter().any(|m| glob_match(m, sender_mask)))
             .unwrap_or(false)
     }
+
+    /// True if `a` and `b` mutually SIGNORE each other (either one has the other on
+    /// their SIGNORE list): a bidirectional block — neither sees the other's channel
+    /// or PM messages, triggered by whichever one ran SIGNORE.
+    pub fn signore_blocks(&self, a: Uid, b: Uid) -> bool {
+        self.signore_one_way(a, b) || self.signore_one_way(b, a)
+    }
+
+    /// Does `by`'s SIGNORE list match `who`'s current mask?
+    fn signore_one_way(&self, by: Uid, who: Uid) -> bool {
+        let Some(byu) = self.users.get(&by) else {
+            return false;
+        };
+        if byu.signore.is_empty() {
+            return false;
+        }
+        let mask = self.users.get(&who).map(|u| u.prefix()).unwrap_or_default();
+        byu.signore.iter().any(|m| glob_match(m, &mask))
+    }
 }