Wiktionary
undisguisable
a. Impossible to disguise.
Usage examples of "undisguisable".
His eyes were strangely shadowed, reflecting an undisguisable evil in the man who had gained the complete confidence of the new, self-proclaimed King.
Possessed of an undisguisable personality, Kerry had found a way of employing his natural physical peculiarities to his professional advantage.
He had known Victory Smith since the day she came into Lands Command, a spanking new junior lieutenant, a lady with an unplaced name and an undisguisable youthfulness.