half assed - colloquialism meaning incomplete
Today I discovered that half assed isn't some Merkin expression relating, (as ever), to the nether regions of butts and asses or to the more English arse or bum.
Half assed is an expression that has been changed though misuse over the years from half adzed, an adze being a tool used for shaping wood. In the old days carved items would have been fully adzed or half adzed, the latter only being carved at the front where it was visible, and therefore being less expensive. In the mind of a true artisan however, it was only superficially complete.
So...there's my half assed attempt at an explanation, hopefully there isn't a full assed version elsewhere.