Absent
Middle English: via Old French from Latin absens, absent- ‘being absent’, present participle of abesse, from ab- ‘from, away’ + esse ‘to be’.
wiktionary
From Middle English absent, from Middle French absent, from Old French ausent, and their source, Latin absens, present participle of absum(“to be away from”), from ab(“away”) + sum(“to be”).
From Middle English absenten, from Old French absenter, from Late Latin absentāre(“keep away, be away”).
etymonline
absent (adj.)
"not present, not in a certain place" (of persons), "non-existent" (of things), late 14c., from Old French absent, ausent "absent" and directly from Latin absentem (nominative absens), present participle of abesse "be away from, be absent," from assimilated form of ab "off, away from" (see ab-) + esse "to be" (from PIE root *es- "to be"). Related: Absently; absentness.
absent (v.)
late 14c., "withdraw (oneself), go away, stay away," from Old French absenter "absent (oneself)," from Late Latin absentare "cause to be away," from Latin absentem (see absent (adj.)). Related: Absented; absenting.
absent (prep.)
"in the absence of," 1944, principally from U.S. legal use, from absent (adj.).