pop off (at the mouth) v.
1. to make a fuss about.
|Northern Automotive Jrnl 18-19 47: To get swelled up with anger and pop off at the mouth is like steam blowing off at the safety valve of the boiler. It is wasted energ.|
|Hungry Men 111: ‘You are getting smart now.’ ‘Forget it,’ Acel said. ‘I’m just poppin’ off. It’s none of my business.’.|
|Big Heat 76: Keep those people in mind [...] when you’re popping off about your own serene little corner of Heaven.|
|(con. 1920s) South of Heaven (1994) 157: Have you been popping off around camp about this?|
2. to confess, to tell the truth.
|Story Omnibus (1966) 37: Pop off, you lightweight, or I will.‘Fly Paper’|
3. to joke.
|On Broadway 28 Nov. [synd. col.] William Lyon Phelps pops off: ‘For a sense of victory instead of failure and defeat, readers might turn to the sports pages.’.|
|From Here to Eternity (1998) 580: As a joke, it did not come off very well. [...] ‘Shut up, Mack,’ the Sgt said to Prew. ‘The more you pop off, the harder you make it for on yourself.’.|
4. to talk in an enthusiastic or aggressive, threatening manner.
|Spanish Amer. (Roy, NM) 24 Jan. 12/1: Certain events [...] have grated our nerves [...] it would be very easy for us to ‘pop off’ and say things which — though true — might get us in bad.|
|Honolulu Adveriser (HI) 6 July 11/6: Even the coach of the defeated Hilo crews pops off loudly about Nicholl’s ability.|
|Folk-Say 202: A man that has to git up at five-thirty hasn’t got any business listenin’ to me pop off.‘Sawmill Divertissements’ in Botkin|
|Letters Home (1944) 8 Sept. 247: I’ve seen many of these tough babies shaking like leaves because of things that don’t phase us quiet fellows who aren’t always popping off about how tough we are or what we’ll do to the enemy.|
|Bound for Glory (1969) 100: Quit popping off at your mouth!|
|Criminal (1993) 73: I was just popping off.|
|In the Life 93: You know me and my mouth—it forgets I’m there and starts popping itself off. [...] my yapper keeps doing a big sales pitch.|
|Thief 415: I got sort of rowdy [...] I guess I popped off quite a bit.|
|King of the World 157: Now here comes Cassius Clay popping off and abusive and loud.|
|‘Kill You’ [lyrics] You better kill me! I’ma be another rapper dead / for poppin off at the mouth with shit I shouldn’ta said.|
5. to brag, to boast.
|Cry of the Owl (1968) 256: What do you mean by popping off to every dope who looks at you that I kept you in New York?|
|Pop. 1280 in Four Novels (1983) 452: It sure ain’t my fault if Ken [...] pops off all over town about what a tough fella he is.|
6. to criticize.
|Sl. U. 150: I don’t know why my dad is always popping off about my clothes.|