Occasionally used scabbard with English sword (5)
I believe the answer is:
sabre
'sword' is the definition.
(sabre is a kind of sword)
'occasionally used scabbard with english' is the wordplay.
'occasionally used' indicates alternate letters.
'with' says to put letters next to each other.
'english' becomes 'e' (abbreviation).
The alternating letters of 'scabbard' are 'sabr'.
'sabr'+'e'='SABRE'
(Other definitions for sabre that I've seen before include "Bares (anag.)" , "Heavy cavalry sword" , "Walt --, cartoonist" , "Sword with curved blade" , "weapon" .)