"to drink freely and revel noisily," 1550s, from French carousser "drink, quaff, swill," from German gar aus "quite out," from gar austrinken; trink garaus "to drink up entirely." Frequently also as an adverb in early English usage (to drink carouse).
suffix forming nouns of action from verbs, mostly from Latin and French, meaning "act of ______ing" (such as survival, referral), Middle English -aille, from French feminine singular -aille, from Latin -alia, neuter plural of adjective suffix -alis, also used in English as a noun suffix. Nativized in English and used with Germanic verbs (as in bestowal, betrothal).
"noisy commotion," 1746, Cambridge student slang, of uncertain origin, perhaps related to rousel "drinking bout" (c. 1600), a shortened form of carousal. Klein suggests a back-formation from rouse (n.), mistaken as a plural (compare pea from pease).
<a href="https://www.etymonline.com/word/carousal">Etymology of carousal by etymonline</a>
Harper, D. (n.d.). Etymology of carousal. Online Etymology Dictionary. Retrieved $(datetime), from https://www.etymonline.com/word/carousal