intrude

American Heritage® Dictionary of the English Language, Fourth Edition

1. v. To put or force in inappropriately, especially without invitation, fitness, or permission: intruded opinion into a factual report.
2. v. Geology To thrust (molten rock) into preexisting rock.
3. v. To come in rudely or inappropriately; enter as an improper or unwanted element: "Unpleasant realities have intruded on [his] presidential dreams” ( Alexander Stille).

Century Dictionary and Cyclopedia

1. To thrust in; bring in forcibly.
2. To thrust or bring in without necessity or right; bring forward unwarrantably or inappropriately: often used reflexively.
3. To push or crowd in; thrust into some unusual, improper, or abnormal place or position: as, intruded rocks or dikes in a geological formation. In entomology an intruded part or organ is one that is nearly concealed in a hollow of the supporting parts, only the apex being visible.
4. To enter forcibly; invade.
5. To come or appear as if thrust in; enter without necessity or warrant; especially, to come in unbidden and unwelcomely: as, to intrude upon a private circle; to intrude where one is not wanted.
6. Synonyms Encroach upon, Infringe upon, etc. See trespass, v. i. Intrude, Obtrude. The essential difference between these words lies in the prepositions: intrude, to thrust one's self into places, invading privacy or private rights; obtrude, to thrust one's self out beyond modesty or the limits proper to ourselves, and offensively against the attention, etc., of others.

Wiktionary

1. v. to enter without permission

GNU Webster's 1913

1. v. To thrust one's self in; to come or go in without invitation, permission, or welcome; to encroach; to trespass
2. v. To thrust or force (something) in or upon; especially, to force (one's self) in without leave or welcome
3. v. obsolete To enter by force; to invade.
4. v. (Geol.) The cause to enter or force a way, as into the crevices of rocks.

WordNet 3.0

1. v. search or inquire in a meddlesome way
2. v. enter uninvited
3. v. enter unlawfully on someone's property
4. v. thrust oneself in as if by force