Is appropriate (4)
'is appropriate' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for fits that I've seen before include "Is of the right shape and size" , "Seizures" , "feels comfortable" , "Paroxysms" , "Sudden uncontrollable attacks" .)
'is appropriate' is the definition.
(to suit is to be appropriate for)
This is the entire clue.
(Other definitions for suits that I've seen before include "Hearts, clubs, diamonds, spades" , "Befits" , "Formal garments" , "cards" , "Sets of clothes designed to be worn together" .)