Intrepid Duke lacking army, you claimed? (9)
I believe the answer is:
dauntless
'intrepid' is the definition.
(synonyms)
'duke lacking army you claimed?' is the wordplay.
'duke' becomes 'd' (abbreviation).
'lacking' becomes 'less' (I've seen this in another clue).
'army you' becomes 'aunt' (I can't justify this - if you can you should believe this answer much more).
'claimed?' indicates putting letters inside (inserted letters are claimed by another word).
'd'+'less'='dless'
'dless' enclosing 'aunt' is 'DAUNTLESS'.
Can you help me to learn more?
(Other definitions for dauntless that I've seen before include "Boldly determined" , "Intrepid" , "Resolute" , "Brave" , "Bold" .)