Gimcrack

Gimcrack \JIM-krak\ , noun;
1. A showy but useless or worthless object; a gewgaw
adjective;
1. Tastelessly showy; cheap; gaudy

This word dates to the 1610's with the definition "showy person" and the sense of "trifle" is first attested in 1839. The origin of gimcrack is uncertain, but it may be an alteration of gibecrake, which is a kind of ornament on wooden furniture. Alternatively, it could be a combination of giber + crak (Old French "to rattle, shake" + Middle English "sharp noise, crack"). In the 18th and 19th centuries the word was also used to mean "a person who has a turn for mechanical contrivances." Gimgrack may be a forebear of gimmick.

I really like the word gewgaw, so I had to look up its etymology too:
It dates to the early 13th century with the form giuegaue, definitely a result of reduplication, possibly connected with Old French gogue ("rejoicing, jubilation; joke, prank, mockery, game") or jou-jou ("toy"). Jou-jou is a baby-talk word derived from jouer ("to play" from Latin jocare).

While we're on the topic of reduplication: whimsy by The Virtual Linguist

Today's word and the first definition were both taken from Dictionary.com's 'Word of the Day' for Thursday, March 3
Etymologies come from the Oxford English Dictionary and/or Etymonline.com