"ineffectual," 1932; "Dictionary of American Slang" suggests it is perhaps a humorous mispronunciation of haphazard. Compare half-hearted.
also halfhearted, "showing little enthusiasm," early 15c.; see half + -hearted. Related: halfheartedly; halfheartedness. English in 17c. had also half-headed "stupid."
updated on October 10, 2017
half seas over