In crosswords, the pen may be more effective than this (5)
I believe the answer is:
sword
'be more effective than this' is the definition.
The definition suggests a singular noun which matches the answer.
'in crosswords the pen' is the wordplay.
'in' indicates the answer is hidden within the clue.
'SWORD' is hidden within 'crosswords pen'.
'may' is the link.
Can you help me to learn more?
(Other definitions for sword that I've seen before include "Sharp weapon" , "killer?" , "Two-edged weapon" , "Double-edged weapon" , "Bladed weapon" .)