-ee

Added to transitive verbs to form words meaning a person or thing that is the object of that verb (i.e., to whom or to which an action is done).

Less commonly added to intransitive verbs to form words meaning a person or thing that is the subject of that verb (that is, who or that does an action).

(law) Used to form words meaning a person who is the other party to a contract or other transaction involving a person described by the corresponding word ending in -or.

(medicine) Used to form words meaning a person who has undergone a particular medical procedure.

Irregularly added to nouns to mean a person somehow associated with the object denoted by the noun.