The synonym is "saying" - the meaning of "saw" is an old proverb or truism.
Other synonyms might be shibboleth or slogan.
"Story" is a synonym that starts with "s" for news.
substantial
The synonym is "saluted" in the sense of applauding an action.
Sailor is a synonym for mariner.
sailor, shipmate, seafarer
synonym
savor
Scope out is one suitable synonym.
Spear is a synonym for lance. It begins with the letter S.
scene, sign
scope ?
A synonym for cannabis that starts with S is sinsemilla.