Green’s Dictionary of Slang

squib v.

to fire a gun; also in fig. use.

1798		T.G. Fessenden ‘Political Pepper-Pot’ Poems (1804) 61: The poet, nimbly, trips it back / Over the Union courses rapid, / And squibs each Jacobinick saphead.
1816		W.T. Moncrieff All at Coventry I i: [a barber speaks] I dress’d him when I lived on Mutton Hill, till, being late one morning, he dressed me, pulled my nose with mine own tongs, squibbed me all the way down the stairs with my own powder-bag, and then discharged half a dozen balls at my head [...] Yes, washballs, Tommy.
1821–6		‘Bill Truck’ Man o’ War’s Man (1843) 296: There were plenty laughing and squibbing at me slily.
c.1838		G.W.M. Reynolds ‘The House Breaker’s Song’ in Farmer Musa Pedestris (1896) 123: And if the swell resist our ‘Stand!’ / We’ll squib without a joke.
1849		Bell’s Life in Sydney 4 Aug. 3/2: He invested a consi- derable sum of money in tho purchase of a gun [...] with which he first began to ‘squib away’ at the birds.

In phrases

squibbed off (adj.)

(US) shot, murdered.

1939		R. Chandler Big Sleep 159: You made a crack when you were up there that night – the night Joe got squibbed off.
1945		R.L. Bellem ‘Suicide Stunt’ Speed Detective Apr. 🌐 ‘It means he was squibbed off.’ ‘Squibbed off?’ ‘Murdered.’.

squib off (v.)

(Aus.) to explode.

1852

G.C. Mundy Our Antipodes III 398: Port Phillip, rejoicing in its new title of Victoria, had squibbed off all her spare powder in pyrotechnical merry-makings.