Skirt-like garment Liberal leader included in gear (4)
I believe the answer is:
kilt
'skirt-like garment' is the definition.
(Scottish skirt)
'liberal leader included in gear' is the wordplay.
'leader' suggests taking the first letters.
'included in' indicates putting letters inside.
'gear' becomes 'kit' (kit is a kind of gear).
The initial letter of 'liberal' is 'l'.
'l' going into 'kit' is 'KILT'.
(Other definitions for kilt that I've seen before include "Pleated tartan skirt" , "Bone; circle line" , "Highland garb" , "Scottish garb" , "Tartan skirt worn in Scotland" .)