A person who secretly disrupts a group's activities from within the group, particularly by encouraging or committing illegal acts to discredit the group or expose them to prosecution; an instigator, troublemaker.

A female agent provocateur; a woman who incites someone to do something, especially something incriminating.

a catalyst

A person who organizes the publicity for a firm or organization, and acts as an intermediary with the press and other media

plural of press agent

A potent herbicide and defoliant used by US forces in the Vietnam War.

(chemistry) Any substance that oxidizes, or receives electrons from, another; in so doing, it becomes reduced.

(chemistry) Any substance that reduces, or donates electrons to, another; in so doing, it becomes oxidized.

A person who finds jobs for actors, models, and other people in the entertainment business.

The substance that creates the buoyancy of a balloon or other airship; normally hydrogen, helium or hot air.