Fixed dress I had (5)
I believe the answer is:
rigid
'fixed' is the definition.
(I've seen this before)
'dress i had' is the wordplay.
'dress' becomes 'rig' (rig is a kind of dress).
'i had' becomes 'id' (I'd).
'rig'+'id'='RIGID'
(Other definitions for rigid that I've seen before include "strict" , "Unable to bend" , "unwilling to move" , "Stiff, unmoving" , "Firmly fixed" .)