Current doctor, frightfully fit (5)
I believe the answer is:
drift
'current' is the definition.
(can be similar in meaning in navigation contexts)
'doctor frightfully fit' is the wordplay.
'doctor' becomes 'dr' (abbreviation).
'frightfully' is an anagram indicator (I've seen this in other clues).
'fit' anagrammed gives 'ift'.
'dr'+'ift'='DRIFT'
(Other definitions for drift that I've seen before include "General meaning or flow" , "(Of snow) blow into heaps" , "General trend - current travel" , "Move with wind and tide" , "Stray" .)