v. 1 tr. a find access into or through, esp. forcibly. b (usu. foll. by with) imbue (a person or thing) with; permeate. 2 tr. see into, find out, or discern (a person's mind, the truth, a meaning, etc.). 3 tr. see through (darkness, fog, etc.) (could not penetrate the gloom). 4 intr. be absorbed by the mind (my hint did not penetrate). 5 tr. (as penetrating adj.) a having or suggesting sensitivity or insight (a penetrating remark). b (of a voice etc.) easily heard through or above other sounds; piercing. 6 tr. (of a man) put the penis into the vagina of (a woman). 7 intr. (usu. foll. by into, through, to) make a way. penetrable adj. penetrability n. penetrant adj. & n. penetratingly adv. penetration n. penetrative adj. penetrator n.
[ L penetrare place or enter within f. penitus interior ]