procession
The word you're after is sweepstake
battles
crevasse
Some eight letter words with the seventh letter S are:bigamistchildishdisguiseflourishgoldfishgoodnessinterestlanguishmotoristoptimismprincesssuitcase
Mammals is the word.
Sponsor.
shortstops
satisfying
foodstalls
The only 7-letter English words are farside (s is 4th letter) and fridges (s is 7th letter).
acrobaticsaerobaticsschematicskinematicspragmaticsasthmatics
Toothbrush