Speak without restraint (3,3)
I believe the answer is:
let rip
'speak without restraint' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for let rip that I've seen before include "Talk aggressively" , "Abandon restraint - allow to tear" , "Go wild" , "Vent feelings" , "Act without restraint" .)