вдвоем, тет-а-тет, меж четырех глаз, один на один, с глазу на глаз, наедине, без посторонних
без свиде́телей
Наедине с кем-л., без посторонних.
"Life is far too important a thing ever to talk seriously about." Oscar Wilde
"Free speech carries with it some freedom to listen." Warren E. Burger
"Honor is not the exclusive property of any political party." Herbert Hoover
"Hitch your wagon to a star." Ralph Waldo Emerson