Head on and on, covering Italy (5)
I believe the answer is:
onion
'head' is the definition.
(I've seen this before)
'on and on covering italy' is the wordplay.
'and' is a charade indicator (letters next to each other).
'covering' says to put letters next to each other (on top of in down clue).
'italy' becomes 'i'.
'on'+'i'='oni'
'on' put after 'oni' is 'ONION'.
(Other definitions for onion that I've seen before include "Strong tasting vegetable" , "One may be set" , "Tear-inducing edible bulb" , "Alliaceous plant" , "Plant with edible bulb" .)