Goofball

Noun

 * 1)  A foolish or silly person.
 * If that goofball would put half the effort into her studies as she does into her juggling, she might do very well.
 * 1)  A pill or tablet containing a pharmaceutical which has hypnotic or intoxicating effects, especially a barbiturate.
 * 2) *1953, "Capsules," Time, 27 Apr.,
 * Strong Cobb & Co. of Cleveland announced a new barbiturate which in overlarge doses will turn the stomachs of "goofball" addicts and would-be suicides.

Adjective

 * 1) Silly.
 * He announced, with his usual goofball humor, that he'd like to marry me!

Thesaurus
Amytal, Amytal pill, Demerol, Dolophine, H, Luminal, Luminal pill, M, Mickey Finn, Nembutal, Nembutal pill, Seconal, Seconal pill, Tuinal, Tuinal pill, alcohol, amobarbital sodium, analgesic, anodyne, barb, barbiturate, barbiturate pill, black stuff, blue, blue angel, blue devil, blue heaven, blue velvet, butterfingers, calmative, chloral hydrate, clumsy, codeine, codeine cough syrup, depressant, depressor, dolly, downer, dub, duffer, foozler, foul-up, fumble-fist, goof, goofer, hard stuff, heroin, hick, hop, horse, hypnotic, junk, knockout drops, laudanum, liquor, lotus, lummox, lump, meperidine, methadone, morphia, morphine, muff, muffer, narcotic, opiate, opium, pacifier, pain killer, paregoric, pen yan, phenobarbital, phenobarbital sodium, purple heart, quietener, rainbow, red, rube, scag, secobarbital sodium, sedative, shit, sleep-inducer, sleeper, sleeping draught, sleeping pill, slob, smack, sodium thiopental, somnifacient, soother, soothing syrup, soporific, stumblebum, stumblebunny, tar, tranquilizer, turps, white stuff, yellow, yellow jacket

Etymology
From goof + ball