Difficult to hold large live weapon (7)
I believe the answer is:
halberd
'weapon' is the definition.
(halberd is a kind of weapon)
'difficult to hold large live' is the wordplay.
'difficult' becomes 'hard' (synonyms).
'to hold' indicates putting letters inside.
'large' becomes 'L' (eg in clothes sizes).
'live' becomes 'be' (synonyms).
'l'+'be'='lbe'
'hard' going around 'lbe' is 'HALBERD'.
(Other definitions for halberd that I've seen before include "Sharp instrument" , "Old weapon" , "Ancient weapon" , "Combined spear and battleaxe" , "Ancient battle-axe" .)