Almost all men smarten up without one direction from a source of power (6,4)
I believe the answer is:
engine room
'a source of power' is the definition.
(I've seen this before)
'almost all men smarten up without one direction from' is the wordplay.
I cannot really see how this works, but
'one' could be 'i' (Roman numeral) and 'i' is present in the answer.
'direction' could be 'ne' (NE is an example) and 'ne' is found in the answer.
'smarten' could be 'groom' (I've seen this before) and 'groom' is present in the remaining letters.
'from' could be 'e' (I've seen this in other clues) and 'e' is found in the answer.
A single letter 'n' remains which might be clued in a way I don't understand.
This explanation may well be incorrect...
Can you help me to learn more?
(Other definitions for engine room that I've seen before include "Source of strength" , "hub of activity" , "basis of the Navy's power?" , "Source of naval power" .)