Peacekeepers given supply of coal, perhaps showing no appreciation (10)
I believe the answer is:
ungrateful
'showing no appreciation' is the definition.
(someone ungrateful doesn't appreciate things)
'peacekeepers given supply of coal' is the wordplay.
'peacekeepers' becomes 'UN' (United Nations, peacekeeping organisation).
'given' says to put letters next to each other.
'supply of coal' becomes 'grateful' (a full grate of coal).
'un'+'grateful'='UNGRATEFUL'
'perhaps' acts as a link.
(Other definitions for ungrateful that I've seen before include "no thanks" , "Thankless" , "Disagreeable" .)