gainsayer

Etymology
From, equivalent to.

Noun

 * 1) One who contradicts or denies what is alleged; an opposer.
 * 2) A person who gainsays others; a disagreeable person.
 * 3) * 2000, Robin McKie, "'Super Brain' to eclipse the Net adds to power of machines," The Observer at guardian.co.uk, 21 May (retrieved 8 Sep. 2008):
 * This urge to ensure the continued viability of UK science is balanced by warnings that such a system brings closer the day when computers will take over the running of the world and discard humanity. One such gainsayer is Bill Joy, inventor of the web language Java and chief scientist at computer giant Sun Microsystems.
 * This urge to ensure the continued viability of UK science is balanced by warnings that such a system brings closer the day when computers will take over the running of the world and discard humanity. One such gainsayer is Bill Joy, inventor of the web language Java and chief scientist at computer giant Sun Microsystems.