Other forms: intruded, intruding, intrudes
To intrude is to come in where you are not wanted. Intrude on their grief, sorry to intrude, intrude into private life.
The prepositions are on and into. Sorry to intrude is a standard apology on arriving unannounced. Intrude on somebody's privacy or grief is the phrase used about press behaviour and is a serious complaint. Note intruder, which usually means somebody who has broken in; intrusive, which of a question or a thought means unwelcome; and intrusion, which in geology means rock forced into other rock.
1verbintrudeTo come in where you are not wanted.
“Loud music from next door intruded on our quiet evening.”
intrude is an unwanted entering.
Latin intrudere is in-, into, plus trudere, to thrust — the same verb as in protrude and obtrude. Intruding is thrusting yourself in, which is more forceful than the polite apology suggests.
Proto-Indo-European
*trewd-
Latin
intrudere
English, today
intrude
Built from
From Latin intrudere, from in- + trudere (“to thrust”).
Etymology from Wiktionary, CC BY-SA