Why “Whom“ Instead of “Who“?

Question

I got this question from a book. In opinion both whom and who sounds correct. The Question is. "The man whom i thought was thoroughly honest proved to be a swindler." \nBut my book says the answer should be "whom". \n

Answer 1

You should use whom when referring to the object of a verb or preposition. When in doubt, try this simple trick: If you can replace the word with “he”' or “'she,” use who. If you can replace it with “him” or “her,” use whom. Who should be used to refer to the subject of a sentence.

Answer 2

Whom is for an object and Who is for a subject.

To figure out which one is correct, it helps to try to rephrase the statements by replacing who with he/she and whom with him/her.

Take the sentence "She is the woman who played piano at the concert." I can break this into two sentences: "She is the woman. She played piano at the concert."

In the case of your sentence, the rephrase goes something like "I thought him thoroughly honest."

Answer 3

Great practical advice Erick and Ilona!

The main difference between 'who' and 'whom' is their pronoun case.

'Who' is subjective and therefore performs an action.

'Whom' is objective and therefore passive.

This is a popular teaching point for L1 and L2 learners alike, so I would also happily add some extra technical information here to help further educate anyone else interested.

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Outside of forming questions, which are a whole different can of worms grammatically, the application of the pronouns in question, 'who' and 'whom', applies mostly to adjective clauses.

Adjective clauses are subject/predicate combinations whose sole purpose in a sentence is to describe a noun.

Much like the original poster's example, the following sentences will be independent clauses with adjective clauses sandwiched into them.

The independent clause will outside of the [ ... ]

The adjective clause will be inside of the [ ... ]

First, the subjective case:

The woman [who is over there eating ice cream] is my mother.

The adjective clause describes the woman. She is eating.

Your younger brother [who always plays pranks on me] needs to back off.

The adjective clause describes the brother. He plays pranks.

That guy [who plays piano all night] sounds terrible.

The adjective clause describes that guy. The guy plays the piano.

Now, the objective case:

The man [whom I am meeting tonight after work] is a wanted criminal.

The adjective clause describes the man, but the man is doing the meeting in this adjective clause.

The woman [for whom you've all been waiting] is finally here!

The adjective clause describes the woman, but she has not been waiting.

The person [from whom you stole money] is quite angry.

The adjective clause describes the person, but the person did not steal anything. I did.

Of course, each of the adjective clauses showcased here can have their pronouns replaced with their colloquial counterpart 'that', but when you are trying to sound more formal, apply the fancier 'who' and 'whom'.