Raising hat, single man's meticulous (8)
I believe the answer is:
diligent
'meticulous' is the definition.
(I've seen this before)
'raising hat single man's' is the wordplay.
'raising' is a reversal indicator.
'hat' becomes 'lid' ('lid' can be a synonym of 'hat').
'single' becomes 'i' (one).
'man' becomes 'gent' (gent is a kind of man**).
'lid' backwards is 'dil'.
'dil'+'i'+'gent'='DILIGENT'
(Other definitions for diligent that I've seen before include "Taking trouble" , "Industrious" , "Showing care and effort" , "Putting care and effort into work" , "Working hard and conscientiously" .)