Stop by six and rest (5)
I believe the answer is:
visit
'stop by' is the definition.
(I've seen this in another clue)
'six and rest' is the wordplay.
'six' becomes 'VI' (Roman numerals).
'and' says to put letters next to each other.
'rest' becomes 'sit' (I've seen this in other clues).
'vi'+'sit'='VISIT'
(Other definitions for visit that I've seen before include "Pay social call" , "Call upon" , "pop by" , "Come to see" , "Look up" .)