Green’s Dictionary of Slang

a buffoon, a blockhead, a dolt; according to Nares (cit. 1822), these are the only pre-20C cits., orig. noted in Todd’s edition of Johnson’s Dict.

a.1631		Donne Satires iv 117: Like a bigge wife, at sight of lothed meat, / Ready to travail; so I sigh and sweat / To heare this Makeron talke in vaine [N].
a.1633		R.B. In Memoriam, Donne’s Poems 401: A Macaroon And no way fit to speake to clouted shoone [N].
1822		R. Nares Gloss. (1888) II 536: macaroon, s. An affected busybody; from maccaroni, Italian.
1942		P. Wylie Generation of Vipers 19: The radio set on the common man’s bedside table is a thundering rebuke to the reliability of the cluck beside it and the macaroon singing over it.