As nouns the difference between sitdown and situp
is that sitdown is while situp is .
situp
English
Noun
(
en noun)
* {{quote-news, year=2007, date=April 2, author=Jessica Kowal, title=Lacking Big-City Luster, Junior Miss Carves a Niche, work=New York Times citation
, passage=The girls giggled during the kick line and forced smiles during push-ups,
situps and twists.}}