Merriam-Webster's Word of the Day for April 13, 2012 is:

querulous • \KWAIR-yuh-lus\  • adjective
1 : habitually complaining 2 : fretful, whining

Examples:
“Are we there yet?” asked a querulous voice from the back seat of the car.

"In his personal affairs [Joseph] Roth is querulous here to the point of annoyance. He complains about everything: his health, his squabbles with editors, the shabby hotels where he lived, the bad translations of his work, his problems with women and, most of all, his unending financial woes, some of them self-inflicted by the penchant for drink that contributed to his early death." — From a book review by Larry Rohter in the New York Times, March 4, 2012

Did you know?
English speakers have tagged fearful whiners "querulous" since late medieval times. The Middle English form of the word, "querelose," was an adaptation of the Latin adjective, "querulus," which in turn evolved from the Latin verb "queri," meaning "to complain." "Queri" is also an ancestor of the English words "quarrel" and "quarrelsome," but it isn't an ancestor of the noun "query" (meaning "question"). No need to complain that we're being coy; we're happy to let you know that "query" descends from the Latin verb "quaerere," meaning "to ask."