A large butt seen in motor programme (8)
I believe the answer is:
calendar
'programme' is the definition.
(thesaurus)
'a large butt seen in motor' is the wordplay.
'large' becomes 'l'.
'butt' becomes 'end' (I've seen this before).
'seen in' means one lot of letters goes inside another.
'motor' becomes 'car' (I've seen this before).
'a'+'l'+'end'='alend'
'alend' put inside 'car' is 'CALENDAR'.
(Other definitions for calendar that I've seen before include "list of appointments" , "Date chart" , "series of dates" , "List of dates of land race" , "Almanac" .)