Points a weapon out as a threat (6)
I believe the answer is:
menace
'a threat' is the definition.
(I know that threat can be written as menace)
'points a weapon out' is the wordplay.
'points' becomes 'en' (two compass points).
'a weapon' becomes 'mace'.
'out' means one lot of letters goes inside another.
'en' placed within 'mace' is 'MENACE'.
'as' acts as a link.
(Other definitions for menace that I've seen before include "A threatening quality" , "ominous atmosphere" , "Harmful person" , "Threat, show of hostility" , "Threat, danger" .)