Set off carrying a gun: was on foot (6)
I believe the answer is:
strode
'on foot' is the definition.
The answer and definition are different parts of speech. However, past participle verbs and adjectives can sometimes mean the same thing.
'set off carrying a gun' is the wordplay.
'off' is an anagram indicator.
'carrying' indicates putting letters inside.
'a gun' becomes 'rod' (rod is a kind of gun).
'set' is an anagram of 'ste'.
'ste' enclosing 'rod' is 'STRODE'.
'was' is the link.
Can you help me to learn more?
(Other definitions for strode that I've seen before include "Galumphed" , "went on foot" , "Walked fast with long steps" , "Paced" .)