One entry found for impenetrable.

Entry Word: impenetrable
Function: adjective
Text: 1 impossible to get through or into <the ancient temple was surrounded by vast stretches of impenetrable jungle>
Synonyms impassable, impermeable, impervious
Related Words close, compact, dense, thick; compressed, condensed; sturdy, substantial, tough; firm, frozen, hard, solid, stiff; inflexible, rigid, unbending, unyielding
Near Antonyms soft, squishy; bendable, elastic, flexible, giving, malleable, pliable, yielding; absorbent, porous
Antonyms negotiable, passable, penetrable, permeable
2 being beyond one's powers to know, understand, or explain <the mysteries of that religion are completely impenetrable to outsiders> -- see MYSTERIOUS 1
3 impossible to understand <the textbook's language is completely impenetrable, at least to me> -- see INCOMPREHENSIBLE
4 not allowing penetration (as by gas, liquid, or light) <the container of toxic waste has an impenetrable seal to prevent leaks> -- see TIGHT 1