Light meal? Ate out? (3)
I believe the answer is:
tea
'light meal?' is the definition.
(I've seen this before)
'ate out?' is the wordplay.
'out?' indicates anagramming the letters (out can mean wrong or inaccurate).
'ate' anagrammed gives 'TEA'.
(Other definitions for tea that I've seen before include "Popular drink" , "going to pot?" , "Food" , "Eg, gunpowder, pekoe" , "Popular beverage brewed at home" .)