anything but, in no degree or respect; not in the least:
The plans were anything but definite.
5.
anything goes, any type of conduct, dress, speech, etc., is considered acceptable or valid or is likely to be encountered and tolerated:
That resort is a place where anything goes!
Origin
before 900;Middle Englishani thing, eni thing,Old Englishǣnig thing. See any, thing1
British Dictionary definitions for anything but
anything
/ˈɛnɪˌθɪŋ/
pronoun
1.
any object, event, action, etc, whatever: anything might happen
noun
2.
a thing of any kind: have you anything to declare?
adverb
3.
in any way: he wasn't anything like his father
4.
anything but, by no means; not in the least: she was anything but happy
5.
like anything, (intensifier; usually euphemistic): he ran like anything
Word Origin and History for anything but
anything
n.
late Old English aniþing, from any + thing. But Old English ænig þinga apparently also meant "somehow, anyhow" (glossing Latin quoquo modo).
Idioms and Phrases with anything but
anything but
By no means, not at all, as in He is anything but ambitious for a promotion. William Wordsworth in his long poem, The Prelude (1805–1806), wrote: “Grief call it not, 'twas anything but that.”