Account, you said, with the guys with mental acuteness (6)
I believe the answer is:
acumen
'mental acuteness' is the definition.
'acumen' can be an answer for 'acuteness' (thesaurus). I'm unsure of the 'mental' bit.
'account you said with the guys' is the wordplay.
'account' becomes 'ac' (abbreviation for account).
'you said' becomes 'U' (homophone of 'you').
'with' says to put letters next to each other.
'the guys' becomes 'men' (guy can mean a man).
'ac'+'u'+'men'='ACUMEN'
'with' acts as a link.
Can you help me to learn more?
(Other definitions for acumen that I've seen before include "'Shrewdness, astuteness (6)'" , "Being sharp" , "The ability to make good and quick decisions" , "Shrewdness, sharpness of mind" , "Awareness" .)