Protest expresses relatively overt reaction to events or situations: sometimes in favour, more often opposed.

Wherever governmental policy or economic circumstances or religious orthodoxy or social strictures or media monopoly restrict self-expression in theory, in practice or in appearance, grumbles or interior opposition may spill over into other areas such as culture, the streets or emigration.

Unaddressed protest may grow and foster dissent, activism, riots, insurgency, revolts, and political and/or social revolution, as in:

• Northern Europe in the early 16th century (see Protestant Reformation)
• North America in the 1770s (see American Revolution)
• France in 1789 (see French Revolution)
• United States of America in the late 20th-century (see for example Stonewall riots)
• Serbia in 2000.

Canonical forms of protest include:

• parts of the Anti-globalization movement
• boycotts
• Charta 77
• some cases of culture jamming
• demonstrations
• flag-burning
• non-violent protest
• occupation
• protest marches
• protest songs
• samizdat
• sit-ins
• die-ins
• strike action
• terrorism

Note: In American English the verb "protest" often acts transitively: The students protested the policy. Elsewhere we still find intransitive usage: The students protested against the policy; or: The students protested in favour of the policy.