It stoops to conquer (5)
I believe the answer is:
eagle
This clue might be a double definition.
'it stoops' is the first definition.
The definition suggests a singular noun which matches the answer.
'conquer' is the second definition.
The answer and definition can be both related to competing as well as being verbs in their base form.
Perhaps you can see an association between them that I can't see?
'to' is the link.
Can you help me to learn more?
(Other definitions for eagle that I've seen before include "Symbolic bird of the US" , "Flyer" , "It normally takes two or three shots to shoot this" , "It may soar" , "born hunter" .)