A. penetrable
B. hidden
C. tolerable
D. gentle
Impervious : not allowing fluid to pass through.
Penetrable : allowing things to pass through; permeable.
Hidden : kept out of sight; concealed.
Tolerable : able to be endured.
Gentle : having or showing a mild, kind, or tender temperament or character.
Antonym of Impervious is Penetrable
