Runs into an elderly poet (6)
I believe the answer is:
arnold
'poet' is the definition.
(19th-century poet Matthew Arnold)
'runs into an elderly' is the wordplay.
'runs' becomes 'r' (cricket abbreviation).
'into' is an insertion indicator.
'elderly' becomes 'old' (similar in meaning).
'r' put within 'an' is 'arn'.
'arn'+'old'='ARNOLD'
(Other definitions for arnold that I've seen before include "Matthew --, English poet" , "-- Wesker, playwright" , "Overcome (obstacle)" , "Matthew --; -- Bennett" , "Victorian poet" .)