Cut short attempt to confiscate weapon? One can't be serious (7)
I believe the answer is:
trifler
'one can't be serious' is the definition.
I can't judge whether this defines the answer.
'cut short attempt to confiscate weapon?' is the wordplay.
'cut short' means to remove the last letter.
'attempt' becomes 'try' (synonyms).
'to confiscate' is an insertion indicator.
'weapon?' becomes 'rifle' (rifle is a kind of weapon).
'try' with its last letter taken off is 'tr'.
'tr' going around 'rifle' is 'TRIFLER'.
Can you help me to learn more?
(Other definitions for trifler that I've seen before include "Idler" , "One behaving without seriousness" .)