Mature times

[johnnyno3]

13a. Anything At All.

_ U_ H_ (5)

[piggling]

ought

[hammersgirl]

aught

[squarebear]

I can think of a few words that match but none that fit "anything at all".

[squarebear]

Why would that fit the clue?

[gen2]

This has to be OUGHT because the rest of the clue is

Less than nothing but still something

so (n)OUGHT

[gen2]

I've just realised that NAUGHT also means nothing
so n(AUGHT) is another possibility.

ought and aught are alternative spellings as well

Looks like coin tossing time.

[johnnyno3]

Thanks everyone. there is also a cyptic clue which is for the same answer.
"Less than nothing but still something" Not much help is it?
I'm going for aught,as one dictionary states an example...,anything whatever.."Neither of his parents had aught but praise for him"