Demanding old partner, single bloke (7)
I believe the answer is:
exigent
'demanding' is the definition.
(similar in meaning)
'old partner single bloke' is the wordplay.
'old partner' becomes 'ex' (I've seen this in other clues).
'single' becomes 'i' (one).
'bloke' becomes 'gent' (I've seen this before).
'ex'+'i'+'gent'='EXIGENT'
(Other definitions for exigent that I've seen before include "Exacting, requiring much" , "Pressing; demanding" , "Pressing and urgent" , "Demanding immediate attention" , "Urgent and exacting" .)