Put into words fast (7)
I believe the answer is:
express
I believe this clue is a double definition.
'put into words' is the first definition.
(I've seen this before)
'fast' is the second definition.
(I've seen this before)
(Other definitions for express that I've seen before include "set forth" , "Explicit" , "Squeeze out - quick" , "Rapid" , "for a specific purpose?" .)