intervene

To become involved in a situation to help, stop trouble, or change what happens.

• The police had to intervene.
• She intervened in the dispute between her colleagues.
• Why did the government refuse to intervene?

How to use it: intervene in something (The teacher intervened in the argument.); intervene to do something (A neighbor intervened to stop the fight.)

Similar words: step in, get involved, interfere

Common phrases: intervene in something, intervene to help, police intervene

To happen unexpectedly and stop or delay something else.

• We will leave unless something intervenes.
• An unexpected illness intervened and delayed our trip.
• Nothing intervened to prevent the work from starting.

Similar words: get in the way, intrude

Common phrases: something may intervene, intervene to prevent

To lie or exist between two people, places, things, or times.

• A wall intervenes between the gardens.
• Ten years intervened between their meetings.
• A wide river intervened between the town and the forest.

How to use it: intervene between A and B (A deep valley intervenes between the two villages.)

Similar words: lie between, come between

Common phrases: intervene between something, years intervene

To join an existing court case to protect your own interests.

• The court allowed her to intervene.
• Several organizations applied to intervene in the case.
• He intervened because the judgment could affect his property.

How to use it: intervene in something (The company asked to intervene in the lawsuit.)

Common phrases: intervene in proceedings, permission to intervene, intervene in litigation