Weapon something frightening almost? I'm having it locked up (8)
I believe the answer is:
scimitar
'weapon' is the definition.
(scimitar is a kind of weapon)
'something frightening almost? i'm having it locked up' is the wordplay.
'something frightening' becomes 'scare'.
'almost?' means to remove the last letter (most of the word but not all of it).
'having' is a charade indicator (letters next to each other).
'locked up' is an insertion indicator.
'scare' with its last letter removed is 'scar'.
'im'+'it'='imit'
'scar' enclosing 'imit' is 'SCIMITAR'.
(Other definitions for scimitar that I've seen before include "Curved form of sword" , "Double-edged sword" , "Steel" , "Short curved oriental sword" , "Eastern sword" .)