Doctor pursues mother with old dance (5)
I believe the answer is:
mambo
'dance' is the definition.
(I know this)
'doctor pursues mother with old' is the wordplay.
'doctor' becomes 'mb' (Bachelor of Medicine, Medicinae Baccalaureus).
'pursues' says to put letters next to each other.
'mother' becomes 'ma' (ma can mean mother).
'with' is a charade indicator (letters next to each other).
'old' becomes 'o' (abbreviation).
'mb' after 'ma' is 'mamb'.
'mamb'+'o'='MAMBO'
(Other definitions for mambo that I've seen before include "voodoo woman" , "Quick Caribbean dance" , "voodoo priestess" , "Dance derived from voodoo rituals" , "Latin American dance of Haitian origin" .)