Synonyms for Either:

adj.

dual (adjective)
both, dual, matching, two, coupled.

n.

by the way, not to mention, incidentally, anyway, the fact that, in any case, anyhow, namely, even so. unbelievable, whether or not, it might be that, ultimate, it could be that, Unless, one or the other, couldn't be better/worse/nicer etc., of your life, with/without distinction, unadulterated, conspicuous, not...anything better/worse, like nothing on earth. on the one hand (noun)
Unless, it could be that, it might be that, one or the other, whether or not.

Usage examples for either

  1. She never was found either – The Planet Strappers by Raymond Zinke Gallun
  2. " That I couldn't say, either – Murder in the Gunroom by Henry Beam Piper
  3. He's not at home either sir. – The Man Who Rose Again by Joseph Hocking