Doctor I caught beside the sea (5)
I believe the answer is:
medic
'doctor' is the definition.
(thesaurus)
'i caught beside the sea' is the wordplay.
'caught' becomes 'c' (cricket abbreviation).
'beside' means one lot of letters go next to another (I've seen this in other clues).
'the sea' becomes 'med' (abbreviation of Mediterranean).
'i'+'c'='ic'
'ic' put after 'med' is 'MEDIC'.
(Other definitions for medic that I've seen before include "Physician (informal)" , "Eg, doctor" , "He may offer treatment" , "What was Basutoland" , "Health worker" .)