Hint of tense competition (5)
I believe the answer is:
trace
'hint' is the definition.
(I know that hint can be written as trace)
'tense competition' is the wordplay.
'tense' becomes 't' (abbreviation used in many dictionaries).
'competition' becomes 'race' (race is a kind of competition).
't'+'race'='TRACE'
'of' acts as a link.
(Other definitions for trace that I've seen before include "Vestige, hint" , "Discover whereabouts" , "Track down or make copy" , "Describe, small quantity" , "Small quantity; find" .)