To be ridiculous is to be something highly incongruous or inferior, sometimes deliberately so to make people laugh or get their attention, and sometimes unintendedly so as to be considered laughable and earn or provoke ridicule and derision. It comes from the 1540s Latin "ridiculosus" meaning "laughable", from "ridiculus" meaning "that which excites laughter", and from "ridere" meaning "to laugh". "Ridiculous" is an adjective describing "the ridiculous".

Nonsense is a communication, via speech, writing, or any other symbolic system, that lacks any coherent meaning. In ordinary usage, nonsense is sometimes synonymous with absurdity or the ridiculous. Many poets, novelists and songwriters have used nonsense in their works, often creating entire works using it for reasons ranging from pure comic amusement or satire, to illustrating a point about language or reasoning. In the philosophy of language and philosophy of science, nonsense is distinguished from sense or meaningfulness, and attempts have been made to come up with a coherent and consistent method of distinguishing sense from nonsense. It is also an important field of study in cryptography regarding separating a signal from noise.