Wader I put on twice (4)
I believe the answer is:
ibis
'wader' is the definition.
(ibis is a kind of wader)
'i put on twice' is the wordplay.
'put on' means one lot of letters go next to another.
'twice' becomes 'bis' (I've seen this in other clues).
'i'+'bis'='IBIS'
(Other definitions for ibis that I've seen before include "Bird, sacred to ancient Egyptians" , "sacred creature of Egypt" , "Storklike bird" , "leggy bird" , "Wader once sacred in Egypt" .)