Feeble, insipid

The Collaborative International Dictionary Word definitions in The Collaborative International Dictionary
Wishy-washy \Wish"y-wash`y\, a. [See Wash .] Thin and pale; weak; without strength or substance; -- originally said of liquids. Fig., weak-minded; spiritless. A weak wishy-washy man who had hardly any mind of his own. --A. Trollope.

Wiktionary Word definitions in Wiktionary
a. 1 wavering; lacking in commitment, certainty, or support; namby-pamby. 2 thin or watery.

Douglas Harper's Etymology Dictionary Word definitions in Douglas Harper's Etymology Dictionary
1690s, "feeble or poor in quality," reduplication of washy "thin, watery." Meaning "vacillating" first recorded 1873.

Wikipedia Word definitions in Wikipedia