interfere

Concise Oxford English Dictionary © 2008 Oxford University Press:
interfere/ɪntəˈfɪə(r)/

▶verb

• 1 (interfere with) prevent from continuing or being carried out properly.

  ■ get in the way of.

  ■ handle or adjust without permission.

  ■ Law attempt to bribe or intimidate (a witness).

• 2 intervene without invitation or necessity.

• 3 (interfere with) Brit. euphemistic sexually molest.

• 4 Physics interact to produce interference.

• 5 (of a horse) knock one foot against the fetlock of another leg.

– derivatives
interferer noun,
interfering adjective,
interferingly adverb.

– origin ME: from OFr. s'entreferir ‘strike each other’, from entre- ‘between’ + ferir (from L. ferire ‘to strike’).