Learn a new word every week

whistle-blower /(h)wɪsəl ˌbloʊ(ə)r/
noun
a person who informs on a person or organization engaged in an illicit activity.

DERIVATIVES
whistle-blowing - noun & adjective

Last week's word

conundrum /kəˈnəndrəm/
noun (plural conundrums)
a confusing and difficult problem or question:
one of the most difficult conundrums for the experts.
• a question asked for amusement, typically one with a pun in its answer; a riddle.

THESAURUS
conundrum /kəˈnəndrəm/
noun
1
the conundrums facing policy-makers: PROBLEM, difficult question, difficulty, quandary, dilemma; informal poser.
2
Rod enjoyed conundrums and crosswords: RIDDLE, puzzle, word game; informal brainteaser.

ORIGIN
late 16th century: of unknown origin, but first recorded in a work by Thomas Nashe, as a term of abuse for a crank or pedant, later coming to denote a whim or fancy, also a pun. Current senses date from the late 17th century.