Surprisingly enough, ask as a noun meaning an
Asking, inquiry; thing asked, request.
has been around for more than a thousand years — the verb ask dates from 885 ᴀᴅ, so a bit older than the 1000 ᴀᴅgiven below for the noun. Here are the first and last citations from the OED:
- a1000 Laws of Athelstan §5 in B. Thorpe Anc. Laws Eng. I. 230
Hæfdon ealle ða ǽscean.
- 1886 ‘Cavendish’ Princ. Whist 127
When your three comes down in the next round, it is not an ask for trumps.
However, a draft addition from 2005 points out a recent use, which it labels colloquial, originally Australian, and chiefly Sport lingo:
colloq. (orig. Austral.) (chiefly Sport).
With modifying word or phrase, as a big (also huge, etc.) ask: something which is a lot to ask of someone; something difficult to achieve or surmount. Cf. tall order at tall adj. 8d.
The citations for this sense date only to 1987, and the two most recent ones given are:
- 2000 Rugby World June 25/1
It was a huge ask of my players, but their attitude throughout the week prior to the game was superb.
- 2003 Gloucester Citizen (Nexis) 1 Feb. 48
Every week is a bit of an ask—but the squad is very strong.
It sounds extremely colloquial to my ear, something of recent and casual coinage (although as I showed above, it is actually very old), so I would advise against it in formal writing.