Weak sort of meal (4)
I believe the answer is:
lame
'weak' is the definition.
('lame' can be similar in meaning to 'weak')
'sort of meal' is the wordplay.
'sort of' is an anagram indicator.
'meal' anagrammed gives 'LAME'.
(Other definitions for lame that I've seen before include "Unable to walk normally" , "Rubbish" , "Having impaired walking ability" , "Limping; weak (argument)" , "game" .)