0 used instead of "who" as the object of a verb or preposition:
1 used as the object of a verb or after a preposition when referring to a particular person or when adding information about a person just mentioned:
2 used esp. in questions as the object of a verb or after a preposition, when asking which person or people, or when asking what someone’s name is:
His strongest criticism is reserved for his father, whom he disliked intensely.
He was very contemptuous of 'popular' writers, whom he described as having no talent.
Many of our distant cousins, whom we hadn't seen for years, came to my sister's wedding.
She disliked the president, whom she once described as an 'insufferable bore'.