Small impression made by streak (6)
I believe the answer is:
sprint
'streak' is the definition.
(thesaurus)
'small impression made by' is the wordplay.
'small' becomes 's' (abbreviation - e.g. clothes size).
'impression' becomes 'print' (impression created by a printer).
'made by' is a charade indicator (letters next to each other) (letters written or made by another set of letters).
's'+'print'='SPRINT'
(Other definitions for sprint that I've seen before include "Rush" , "Quick dash" , "Short race at full speed" , "Short fast race" , "Short fast run" .)