Fold suit and tie that is left out (5)
I believe the answer is:
pleat
'fold' is the definition.
(I know that fold is a is a kind of of pleat)
'suit and tie that is left out' is the wordplay.
'suit' becomes 'plea' (I've seen this before).
'and' says to put letters next to each other.
'that is' becomes 'ie' (short for Latin 'id est', 'that is').
'left out' suggests deleting specific letters.
'tie' with 'ie' taken out is 't'.
'plea'+'t'='PLEAT'
(Other definitions for pleat that I've seen before include "Crease" , "Gathering" , "Flat fold of cloth" , "Fold in a skirt" , "Fold sewn or pressed into cloth" .)