1620s, "action of judging," from Latin iudicationem (nominative iudicatio), noun of action from past-participle stem of iudicare "to judge," related to iudicem "a judge" (see judge (n.)).
"deception, escape by artifice or deceit," 1540s, noun of action from elude, or from Medieval Latin elusionem (nominative elusio), noun of action from past-participle stem of Latin eludere.
1510s, "action of besieging" (a sense now obsolete), from French obsession and directly from Latin obsessionem (nominative obsessio) "siege, blockade, a blocking up," noun of action from past-participle stem of obsidere "to besiege" (see obsess). Later (c. 1600), "hostile action of an evil spirit" (like possession but without the spirit actually inhabiting the body). Transferred sense of "action of anything which engrosses the mind" is from 1670s. Psychological sense "idea or image that intrudes on the mind of a person against his will" is from 1901.