In answer to the challenge, the twit raised the weapon (8)
I believe the answer is:
password
'in answer to the challenge' is the definition.
I can't tell whether this defines the answer.
'twit raised the weapon' is the wordplay.
'twit' becomes 'sap'.
'raised' is a reversal indicator (going up in a down clue).
'the weapon' becomes 'sword' (sword is a kind of weapon).
'sap' back-to-front is 'pas'.
'pas'+'sword'='PASSWORD'
'the' is the link.
Can you help me to learn more?
(Other definitions for password that I've seen before include "Secret requirement for access" , "It's something to admit" , "Sign to gain admittance" , "Shibboleth - secret phrase to gain admission" , "Secret phrase needed to gain entry" .)