alter ego, associate, confederate, like-minded fellow, like-minded man, like-minded person, fellow-thinker (can also be used without the hyphen), adherent, adherer, someone who thinks the same way, (мой) (иногда):person [working for] the same cause, (мой) person who feels the same way I do, (мой) person who has the same position on [an issue], kindred spirit (в нек. контекстах), like-minded