penetrate

Concise Oxford English Dictionary © 2008 Oxford University Press:
penetrate/ˈpenɪtreɪt/

▶verb

• 1 go into or through, especially with force.

  ■ (of a man) insert the penis into the vagina or anus of (a sexual partner).

• 2 infiltrate (an organization, competitor's market, etc.).

• 3 understand or gain insight into (something complex or mysterious).

• 4 (as adj. penetrating) (of a sound) clearly heard through or above other sounds.

– derivatives
penetrability noun,
penetrable adjective,
penetratingly adverb,
penetrator noun.

– origin C16 (earlier (ME) as penetration): from L. penetrat-, penetrare ‘go into’.