Becomes weary and in need of rest (5)
I believe the answer is:
tires
'becomes weary and in need of rest' is the definition.
(I've seen this before)
This is the entire clue.
(Other definitions for tires that I've seen before include "Exhausts" , "Wearies" , "Grows weary of rites" , "Becomes weary and in need of rest" , "Weakens" .)