Weary following delay (4)
I believe the answer is:
flag
'weary' is the definition.
(both can mean to tire)
'following delay' is the wordplay.
'following' becomes 'f' (used when citing page numbers etc).
'delay' becomes 'lag' (lag is a kind of delay).
'f'+'lag'='FLAG'
(Other definitions for flag that I've seen before include "National standard" , "Iris - paving slab" , "Plant; paving slab" , "Emblematic rectangular piece of fabric" , "Give a signal" .)