Unusual cut in garment (5)

I believe the answer is:

tunic

'garment' is the definition.
(historical type of garment)

'unusual cut in' is the wordplay.
'unusual' is an anagram indicator.
'cut'+'in'='cutin'
'cutin' anagrammed gives 'TUNIC'.

(Other definitions for tunic that I've seen before include "School garment", "Loose-fitting shirt or cloak", "Schoolgirl's dress", "Knee-length cloak", "Jacket of some soldiers".)