Keep out of sight (3,3)
I believe the answer is:
lay low
'keep out of sight' is the definition.
(I've seen this in another clue)
This is the entire clue.
(Other definitions for lay low that I've seen before include "Flatten" , "Knock down -- tried to avoid detection" , "Bring down - hid" , "kept out of sight" , "Kept out of the limelight" .)