Way writing fluid makes nasty smell (5)
I believe the answer is:
stink
'nasty smell' is the definition.
(I've seen this before)
'way writing fluid' is the wordplay.
'way' becomes 'st'.
'writing fluid' becomes 'ink' (I've seen this before).
'st'+'ink'='STINK'
'makes' acts as a link.
(Other definitions for stink that I've seen before include "Foul smell" , "Horrid smell" , "Pong" , "Smell - great fuss caused" , "trouble" .)