half-baked 
adjective
1Not fully thought through; lacking a sound basis: a half-baked conspiracy theory...
- Last Days, by comparison, is simply small, plumbing the shallow depths of half-baked notions about celebrity and art and depression.
- I jotted down a bunch of things that have been bouncing around my head regarding social software, some half-baked, some fully baked.
- Joking aside, The Lizzie McGuire Movie may sound predictable and half-baked, but it is a surprisingly good film.
Synonyms
not thought through, not fully developed, undeveloped, unformed, hare-brained;
poorly planned, unplanned, ill-conceived, ill-judged;
impractical, unrealistic, unworkable, injudicious, ridiculous
informal crazy, crackpot, cock-eyed
1.1Foolish: a half-baked hippie chick...
- In a jocular vein he speaks about the raw deal meted out to directors by certain half-baked specialists ‘who speak authoritatively’ about cinema.
- Daena may be a half-baked character, but she isn't the film's weakest link.
- Even the half-baked economists at the IMF should know that holding back government spending in a contracting economy is like turning off the engines on an aeroplane in stall.
Synonyms
foolish, stupid, silly, idiotic, doltish, asinine, simple-minded, feeble-minded, empty-headed, hare-brained, feather-brained, feather-headed, brainless, senseless, witless, unintelligent, ignorant;
inexperienced, immature, callow, green, credulous
informal crazy, dim, dopey, dumb, thick, damfool, half-witted, dim-witted, birdbrained, lamebrained, dunderheaded, wet behind the ears, as thick as two short planks
British informal gormless, daft, divvy, dozy
Scottish & Northern English informal glaikit
North American informal dumb-ass, chowderheaded
South African informal dof
West Indian informal dotish