Really relax, with "out" (3)
I believe the answer is:
veg
'really relax with out' is the definition.
(I've seen this in another clue)
This is the entire clue.
(Other definitions for veg that I've seen before include ""Meat and two __ "" , "Food plants" , "Potatoes and cabbages etc" , "Eg, sprouts, parsnips" , "Slob?" .)