—n.
1 a an extortion of payment in return for not disclosing discreditable information, a secret, etc. b any payment extorted in this way.
2 the use of threats or moral pressure.
—v.tr.
1 extort or try to extort money etc. from (a person) by blackmail.
2 threaten, coerce.
Derivatives:
blackmailer n.
Etymology: BLACK + obs. mail rent, OE mal f. ON maacutel agreement
Useful english dictionary. 2012.