Green’s Dictionary of Slang

prone to boasting or showing off; thus bounceably adv.

1823		Morn. Post (London) 11 Dec. 2/4: A dispute arose about a sack, which each claimed; when Fawcett said, You need not be so bounceable about it; George shall fight you for a sovereign.
1827		Egan Anecdotes of the Turf, the Chase etc. 288: [They] may get the same soup for their supper [i.e. execution], if too bouncible.
1832		S. Warren Diary of a Late Physician in Works (1854) III 371: We had exhibited sundry doses of Irish cordial to our friend Tip, under the effects of which he became quite ‘bouncible,’ and ranted about the feat.
1837		‘Now!’ in Rum Ti Tum! in Spedding & Watt (eds) Bawdy Songbooks (2011) III 169: Sal, now since you come to that, And bounceable you get [etc.].
1838		Dickens Oliver Twist (1966) 256: There’s no call to tell a man he is, so bounceably.
1847		Bell’s Life in Sydney 3 Apr. 3/2: [She] became ‘so bouncible’ that he peremptorily told her that she must go home—vanish—mizzle.
1849		Dickens David Copperfield (1991) 87: I heard that Mr. Sharp’s wig didn’t fit him; and that he needn’t be so ‘bounceable’ – somebody else said ‘bumptious’ – about it.
1864, 1867, 1870		Hotten Sl. Dict.
1935		A.J. Pollock Und. Speaks 12/1: Bounceable, boasting liar.