Take many an objective (5)
I believe the answer is:
claim
'take' is the definition.
(I know that take can be written as claim)
'many an objective' is the wordplay.
'many an' becomes 'cl' (I am not sure about this - if you are sure you should give a lot more credence to this answer).
'objective' becomes 'aim' (synonyms).
'cl'+'aim'='CLAIM'
Can you help me to learn more?
(Other definitions for claim that I've seen before include "Allege" , "Right; demand this" , "Assert; request" , "Put in for" , "Assertion of right" .)