Nonsense, twaddle, drivel, bunk, balderdash, poppycock, gobbledygook, trash, rot, bull are comparable when they mean something said or proposed which is senseless or absurd.
Nonsense is the most general of these terms; it may be referred to action or behavior as well as to utterances or to proposals, and it may imply foolery or humbuggery as well as absurdity or senselessness.
Twaddle applies to silly empty utterance and suggests the speech of persons who know nothing about a subject yet talk or write about it foolishly, verbosely, or artlessly.
Drivel implies a flow of such idle, inane, or commonplace talk as might befit an imbecile or an idiot; it is a highly contemptuous term for nonsensical spoken or written utterances.
Bunk is an equivalent of nonsense and applies especially to an utterance (as a speech, an opinion, or a doctrine) which, though lacking in real worth or substance, either by intent or by the gullibility of those who listen or accept, hits the popular fancy because it is pretentious, plausible, or high-sounding.
Balderdash and poppycock may apply to confused, turgid, complex utterances that lack or seem to lack sense, but both words may imply an attempt to mislead or deceive by such utterances and both may suggest an unwillingness to see sense on the part of the one that uses them.
Gobbledygook is used of wordy unintelligible jargon especially when featuring the obscure or technical verbiage of some special field.
Trash, rot, and bull are applicable to utterances regarded as worthless or confusingly inaccurate or misleading.
Trash may stress the empty worthlessness especially of written material and rot, the user's disbelief or disgust.
Bull in its more general use may apply to a grotesque or ludicrous blunder in language, but often it is a slang term denoting trivial, verbose, and commonly boastful or inaccurate utterance or facile speech intended to deceive.