Doctor with hesitation getting small percussion instruments (5)
I believe the answer is:
drums
'percussion instruments' is the definition.
(drum is a kind of percussion instrument)
'doctor with hesitation getting small' is the wordplay.
'doctor' becomes 'dr' (abbreviation).
'with' is a charade indicator (letters next to each other).
'hesitation' becomes 'um' (um is said in hesitation).
'getting' says to put letters next to each other.
'small' becomes 's' (abbreviation - e.g. clothes size).
'dr'+'um'+'s'='DRUMS'
(Other definitions for drums that I've seen before include "Percussion instruments" , "Containers" .)