half-baked

Short definition from Wiktionary

Adjective

1. 1
   Incomplete; (of an idea or scheme) not fully planned or carefully considered, ill-conceived, unsound or badly thought-out; (of a person) foolish or having no common sense.
2. 2
   Under the influence (of alcohol) but not totally baked.
3. 3
   Used other than figuratively or idiomatically: Partially cooked by heating in an oven, either as an accidental outcome or as a work in process.
4. 4
   Alternative spelling of half-baked.