Brown arrived and left (5)
I believe the answer is:
camel
'brown' is the definition.
(camel is a shade of brown)
'arrived and left' is the wordplay.
'arrived' becomes 'came' (come can mean to appear or arrive).
'and' means one lot of letters go next to another.
'left' becomes 'l' (common abbreviation).
'came'+'l'='CAMEL'
(Other definitions for camel that I've seen before include "Yellowish" , "Humped mammal" , "Humped creature" , "One travelling in caravan" , "Humped beast" .)