unfounded

a.无事实根据的，无基础的

unfeigned, unfeignedly, unfettered, unfinished, unfit, unflagging, unflaggingly, unflappability, unflappable, unflinching, unflinchingly, unfocused, unfold, unforeseen, unforgettable, unforgivable, unformed, unforseen, unfortunate, unfortunately, unfreeze, unfriendly, unfrock, unfulfilled, unfurl, ungainliness, ungainly, ungenerous, unget-at-able, unglazed, ungodly, ungovernable, ungracious, ungraciously, ungrammatical, ungrammatically, ungrateful, ungratefully, ungrudging, unguarded,