Foolish mistake made in road to Tyneside? (7)
I believe the answer is:
asinine
'foolish' is the definition.
('asinine' can be similar in meaning to 'foolish')
'mistake made in road to tyneside?' is the wordplay.
'mistake' becomes 'sin'.
'made in' indicates putting letters inside.
'road' becomes 'ai' (I've seen this in other clues).
'to tyneside?' becomes 'ne' (region in North East of England).
'sin' put inside 'ai' is 'asini'.
'asini'+'ne'='ASININE'
(Other definitions for asinine that I've seen before include "Is inane to be foolish" , "simple" , "Absurd" , "Idiotic" , "Donkey-like" .)