One hug could be sufficient (6)
I believe the answer is:
enough
'sufficient' is the definition.
('enough' can be similar in meaning to 'sufficient')
'one hug could be' is the wordplay.
'could be' indicates anagramming the letters.
'one'+'hug'='onehug'
'onehug' anagrammed gives 'ENOUGH'.
(Other definitions for enough that I've seen before include "This is going no further!" , "It's said to be as good as a feast" , "To the required extent" , "An adequate quantity" , "The quantity needed, sufficient" .)