Sun's agony aunt regularly involved in tasteless articles still? (8)
I believe the answer is:
stagnant
'still?' is the definition.
('stagnant' can be a synonym of 'still')
'sun's agony aunt regularly involved in tasteless articles' is the wordplay.
'sun' becomes 's'.
'regularly' means one should take alternating letters (regularly take one letter, leave next etc.).
'involved in' indicates putting letters inside.
'tasteless articles' becomes 'tat' (I've seen this before).
'agony'+'aunt'='agonyaunt'
The alternate letters of 'agonyaunt' are 'gnan'.
'gnan' placed inside 'tat' is 'tagnant'.
's'+'tagnant'='STAGNANT'
(Other definitions for stagnant that I've seen before include "Without vitality" , "hardly moving" , "Moribund" , "making no progress" , "(Of water) motionless" .)