which synonym

The word “which” doesn’t have a single universal synonym, because its replacement depends on how you’re using it in the sentence.

Main options at a glance

• As a question word (interrogative pronoun/determiner):
  • Possible substitutes: “what” (in many questions), sometimes “which one”.
  • Example: “Which do you prefer?” → “What do you prefer?”
• As a relative pronoun in the middle of a sentence:
  • Common substitutes: “that” , sometimes “whatever”, “whichever” in specific meanings.
  • Example: “The book which I bought is new.” → “The book that I bought is new.”

Because “which” is so common and neutral, the best “synonym” in real writing is often just:

• Rephrasing the sentence (splitting it, changing the structure), or
• Using “that” (for things) or “who/whom” (for people) where appropriate.

If you share a specific sentence where you want to replace “which,” I can suggest the most natural alternative for that exact context.