whoever

whoever, who ever, whomever

1. The same distinction applies here as to whatever and what ever, whoever being written as one word when it is an indefinite relative pronoun equivalent to ‘whatever person’ used in statements or commands (Whoever wants it can have it) and when the meaning is ‘regardless of whom’ (Whoever it is, I don't want to see them). Who ever is written as two words when ever is used as an intensifying word and the expression as a whole is equivalent to who on earth, usually in direct questions: Who ever are those people?. See ever ¹.

2. The objective form whomever still occurs but it can sound formal or affected in general contexts:

• To impose his will on whomever he sees comfortably settled —Max Beerbohm, 1920.

In some cases it is wrongly used:

• ☒ …ready at once to relax with whomever came to hand —Anita Brookner, 1992

• ☒ Accepting the poverty it entailed, he [Socrates] appears to have spent all his time in unpaid discussion with whomever would join with him —E. Craig, 2002

(in each case with governs the whole following clause, came to hand and would join with him; the pronoun is the subject of the clause and should therefore be whoever).