...in other words, hugging Granny is foolish (5)
I believe the answer is:
inane
'foolish' is the definition.
('inane' can be similar in meaning to 'foolish')
'in other words hugging granny' is the wordplay.
'in other words' becomes 'ie'.
'hugging' indicates putting letters inside.
'granny' becomes 'nan'.
'ie' placed around 'nan' is 'INANE'.
'is' acts as a link.
(Other definitions for inane that I've seen before include "Vapid, fatuous" , "Devoid of intelligence" , "Witless and pointless" , "Delirious" , "Daft" .)