Caustic

Primary Specifications
Liquid caustic soda (50%) is a clear or opaque liquid.This product is produced certified to NSF/ANSIStandard 60. When shipped in Bayer Polymerscontrolled containers, product retains NSF/ANSI certification. F.O.B. shipments of this product in non-Bayer Polymers controlled containers will not be NSF/ANSI Certified unless a container cleaning
certificate is provided. Barge shipments do not carry NSF/ANSI certification unless special arrangementsare made.

From the website: http://www.bayermaterialsciencenafta.com/products/index.cfm?mode=ds&pp_num=EB7C5DAB-FD47-2D09-BB0EC0835CEE494B&pg_num=EB7C5DBB-9374-20DE-C9BEC19D4582251D

Caustic soda is very dangerous because it is capable of eating away or destroying things.

Insurgent

The Iraqi insurgency is composed of a diverse mix of militias, foreign fighters, all-Iraqi units or mixtures using violent measures against the United States-led multinational force in Iraq in Iraq and the post-2003 Iraqi government, or by propaganda or money supportive thereof. The fighting appears both as armed conflict with the United States-led military coalition, as well as sectarian violence among the different ethnic groups within the population. The insurgents are involved in asymmetric warfare and a war of attrition against the US-supported Iraqi government and US forces, while conducting coercive tactics against rivals or other militias.

http://en.wikipedia.org/wiki/Iraqi_insurgency

My example: The American Revolution was fought by insurgent colonists against the British Redcoats.