Cross river clutching medic, one who's hard to grasp? (7)
I believe the answer is:
mumbler
'one who's hard to grasp?' is the definition.
(someone whose words are hard to hear or grasp)
'cross river clutching medic' is the wordplay.
'cross' becomes 'mule' (a mule is a cross of a donkey and a horse).
'river' becomes 'r' (abbreviation for river).
'clutching' indicates putting letters inside.
'medic' becomes 'MB' (Bachelor of Medicine).
'mule'+'r'='muler'
'muler' going around 'mb' is 'MUMBLER'.
(Other definitions for mumbler that I've seen before include "One who talks indistinctly" , "Indistinct person" .)