Phrasal Verbs with 'Gang'

Gang up

Form a group against something or someone

Example: They GANGED UP to try to stop the new system.

Gang up against

Harass, bully (in a group)

Example: They GANGED UP AGAINST me because I wouldn't accept their ideas.

Gang up on

Harass, bully

Example: They GANGED UP ON him because of the way he spoke.