Green’s Dictionary of Slang

big-note v.

also come the big note
[SE big + note, paper money, currency; come the... v. ]

(Aus.) to boast; usu. as big-note oneself v., to inflate one’s achievements; thus big-noting n., boasting.

[Aus]K. Tennant Joyful Condemned 23: ‘Morton the bustman!’ Rene sneered. ‘Listen to him big-note himself. He’s going to do a bust.’.
[Aus]Baker Drum 126: There is [...] a verbal sense of big note, meaning to exaggerate one’s wealth.
[Aus]D. Hewett Bobbin Up (1961) 177: You’re just big-notin’ yourself, carving out a slice of your own particular glory.
[Aus]A. Buzo Front Room Boys Scene i: I’m not the sort of bloke who big-notes himself.
[Aus]B. Oakley Salute to the Great McCarthy 65: Don’t come the big note with me, Fortune, your next sarcasm might be your last.
[Aus]R. Gerster [bk title] Big-noting: The Heroic Theme in Australian War Writing.
[NZ]McGill Dict. of Kiwi Sl. 14/2: big-note to boast or exaggerate; eg ‘Barry’s bignoting again about how many he’s scored over the years.’ c. 1935.
[Aus]M.B. ‘Chopper’ Read How to Shoot Friends 86: Jimmy Loughnan and me were used to big-noting nitwits who raved on about what they wanted to do.
[NZ]McGill Reed Dict. of N.Z. Sl. [as cit. 1988].
[Aus] Sydney Morning Herald 1 July 🌐 [headline] A spot of big-noting could be the key to a major piano victory.
[Aus]J. Miller Lingo Dict. 16: big note To boast about your own importance.
[Scot]T. Black Ringer [ebook] n.p.: He’s at it, playing up, just trying to big note himself.