First to see abusive poster as constitutional (6)
I believe the answer is:
stroll
'constitutional' is the definition.
(I've seen this before)
'first to see abusive poster' is the wordplay.
'first to' indicates taking the first letters.
'abusive poster' becomes 'troll' (someone posting abuse online).
The first letter of 'see' is 's'.
's'+'troll'='STROLL'
'as' acts as a link.
(Other definitions for stroll that I've seen before include "Constitutional" , "Meander" , "A casual or leisurely walk" , "Saunter in no particular direction" , "Walk casually" .)