Impenetrable - Definition
impenetrable
adj 1: not admitting of penetration or passage into or through;
"an impenetrable fortress"; "impenetrable rain forests"
[ant: penetrable]
2: permitting little if any light to pass through because of
denseness of matter; "dense smoke"; "heavy fog";
"impenetrable gloom" [syn: dense, heavy, impenetrable]
3: impossible to understand; "impenetrable jargon"