Green’s Dictionary of Slang

blow one’s top v.

also blow one’s cap, ...topper
[SE blow, explode + top n. (3)/SE cap/topper n.3 (1); the image is of a volcano]
(orig. US)

1. to lose one’s sanity.

[US]R.J. Tasker Grimhaven 28: Unless you say ‘blew his top’ or ‘blow his topper’; then it means to go crazy.
[US]D. Runyon ‘Romance in the Roaring Forties’ in Runyon on Broadway (1954) 36: Finally he blows his topper.
[US]Louis Jordan ‘But I’ll be Back’ [lyrics] Gonna make you give me back my love / Before I blow my top!
[US]Mezzrow & Wolfe Really the Blues 4I: I saw my first race riot there [...] It left me so shaky I almost blew my top.
[US]‘Blackie’ Audett Rap Sheet 175: I seen as many as three guys a night flop off – blow their tops – and try to commit suicide.
[UK]‘Raymond Thorp’ Viper 116: The cats nearly blew their top and as soon as they could get otuside they rushed for the drug again.
[US]P. Thomas Down These Mean Streets (1970) 300: Can’t you see? I’m flipping, I’m blowing my top.
[US]H. Armstrong in Heller In This Corner (1974) 194: They said ‘This man’s gone crazy. He’s blowing his top.’.

2. (US black) to get drunk.

[US] ‘Hectic Harlem’ in N.Y. Amsterdam News 8 Feb, sect. 2: BLOW YOUR TOP. – To get drunk.

3. (US tramp) to commit suicide, esp. by shooting.

[US]Irwin Amer. Tramp and Und. Sl. 31: blow one’s top.–To commit suicide, correctly, by shooting, although sometimes extended to include any means of self-destruction.

4. (also blow gaff) to lose one’s temper, to become violent [gaff n.2 (4)].

[US]Ersine Und. and Prison Sl.
[US]W.R. Burnett High Sierra in Four Novels (1984) 342: When I got tipped off she was going to get a divorce [...] If it hadn’t been for Barmy I’d have blowed my topper sure.
[US]C. Himes ‘A Penny for Your Thoughts’ in Coll. Stories (1990) 63: That Nazi pilot must be blowing his top.
[Aus]R.S. Close Love me Sailor 151: The old man wasn’t letting Christianson blow any more gaff.
[US](con. 1943–5) A. Murphy To Hell and Back (1950) 109: A hog should have known better [...] but not men, when they blow their toppers.
[US]W.R. Burnett Little Men, Big World 170: Lola’ll look after him till she drops or I blow my topper.
[US]L. Lariar Day I Died 115: You don’t want to blow your top.
[UK]Wodehouse Jeeves and the Feudal Spirit 105: Uncle Tom [...] will blow his top.
[US]‘Ed Lacy’ Men from the Boys (1967) 62: I let go of him. ‘All right. Sorry I blew my cap, buddy.’.
[US]H.S. Thompson letter 23 Aug. in Proud Highway (1997) 390: A Grace Company official blew his top during a visit by Teodoro Moscoso.
[US]‘Red’ Rudensky Gonif 134: Please, God, don’t let me blow my top again.
[Aus]N. Keesing Lily on the Dustbin 46: The baby’s mother ‘took a peep’ at the card he was filling in and nearly ‘blew her top’.
[UK]M. Frayn Now You Know 82: It’s Jacqui blowing her top. Jacqui’s having a great go about something.
[UK]Guardian G2 26 Jan. 9: I know I mustn’t blow my top.

5. to express intense emotion; to become very excited.

[US]Bob Howard & His Boys ‘If You’re a Viper’ [lyrics] Truck on down to the candy store / Blow your top on peppermint candy.
[US]Cab Calloway New Hepsters Dict. in Calloway (1976) 253: blow the top (v.): to be overcome with emotion (delight). Ex., ‘You’ll blow your top when you hear this one’.
[US]C. Himes ‘Make with the Shape’ in Coll. Stories (1990) 110: Well now, what honorably discharged Sergeant Johnny Jones was really blowing his lucky top about [...] was Jessie May’s fine, round gams.
[US]‘Hal Ellson’ Duke 3: That’s the way I dig it. I do it nice. Play it cool. I don’t blow my top like other cats and go out and rob to get stuff.
[US]Kerouac On the Road (The Orig. Scroll) (2007) 215: Dexter Gordon and Wardell Gray blowing their tops before a screaming audience.
[US]Kerouac On The Road (1972) 127: Listen will you to this old tenorman blow his top.
[US]D. Pearce Cool Hand Luke (1967) 57: We let off steam. We blew our tops.
[US]H. Selby Jr Requiem for a Dream (1987) 59: So dont blow your top. Relax.

6. to talk too much.

[US]M.H. Boulware Jive and Sl. n.p.: Blowing your top ... Worthless chatter.
[UK]C. MacInnes City of Spades (1964) 32: You blow your top too much, Mr Stranger.