penetrable

[pen-i-truh-buh l]

Origin of penetrable

1375–1425; late Middle English < Latin penetrābilis, equivalent to penetrā(re) to penetrate + -bilis -ble
Related formspen·e·tra·bil·i·ty, pen·e·tra·ble·ness, nounpen·e·tra·bly, adverbnon·pen·e·tra·bil·i·ty, nounnon·pen·e·tra·ble, adjectivenon·pen·e·tra·bly, adverbself-pen·e·tra·bil·i·ty, nountrans·pen·e·tra·ble, adjectiveun·pen·e·tra·ble, adjectiveun·pen·e·tra·bly, adverb
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2018

Word Origin and History for unpenetrable
adj.

c.1400, from un- (1) "not" + penetrable. The usual word now is impenetrable.

penetrable

adj.

early 15c., "penetrating," from Latin penetrabilis "penetrable, vulnerable," from penetrare (see penetrate). Meaning "capable of being penetrated" is attested from 1530s; figurative use by 1590s. Related: Penetrability.

Online Etymology Dictionary, © 2010 Douglas Harper