The Collins English Dictionary defines "grotesque", in part, as: "[S]trangely or fantastically distorted".

The term derives from the Italian term for grottos (grotteschi), i.e., the ruins in which statuettes of distorted figures were found in the XV and XVI centuries.

Grotesquerie is associated not only with the ironic parody typical of the carnival, but also with the external public expression of a disordered inner state. The grotesque exists in a dialectical relationship with the classical beauty. The notion combines ugliness and ornament, the bizarre and the ridiculous, the excessive and the unreal.
It draws attention to the normatively beautiful in its mockery of it.

In The Female Grotesque, Mary Russo writes: "The images of the grotesque body are precisely those which are abjected from the bodily canons of classical aesthetics.”  …"The classical [beautiful] body is... closed, static, self-contained, symmetrical and sleek... the grotesque body is... multiple and changing... it is identified with... social transformation." In other words, the grotesque body transcends boundaries; it blurs distinctions and creates new forms of beauty.

The Romantic era, with its interest in the dispossessed, in all those who before the age of Revolution had been nameless and invisible, made the grotesque its indispensable adjunct. Victor Hugo, for whom the grotesque was indispensable opposite the sublime, aptly indulged his penchant for antithesis when he claimes that the grotesque is "the richest source nature can offer art." M. Bahktin placed the grotesque at the heart of the carnivalesque spirit.

"The familiar structure of existence is undermined and chaos seems imminent. This aspect is intensified when concrete manifestations of decay appear and a feeling of hopelessness and corruption is developed. The ludicrous aspect, in turn, arises from the farcical quality inherent in such scenes of absurdity and approaching chaos"(Lee Byron Jennings The Ludicrous Demon: Aspects of the Grotesque in German Post-Romantic Prose).

Sublime and grotesque.

"In human nature, praiseworth qualities never are found without concurrent variations that must run through endless shadings to the utmost imperfection. The quality of the terrifying sublime, if it is quite unnatural, is adventurous. Unnatural things, so far as the sublime is supposed in them, although little or none at all may actually be found, are grotesque. Whoever loves and believes the fantastic is a visionary; the inclination toward whims makes the crank. On the other side, if the noble is completely lacking the feeling of the beautiful degenerates, and one calls it trifling. A male person of this quality, if he is young, is named a fop; if he is of middle age he is a dandy. Since the sublime is the most necessary to the elderly, an old dandy is the most contemptible creature in nature, just as a young crank is the most offensive and intolerable." (Immanuel Kant, Observations on the Feeling of the Beautiful and Sublime, trans Goldthwait, 1960, p. 55)

"Monasteries and such tombs, to confine the living saints are grotesque. Subduing one's passions through principles is sublime. Castigation, vows, and other such monks' virtues are grotesque. Holy bones, holy wood, and all similar rubbish, the holy stool of the High Lama of Tibet not excluded, are grotesque. Of the works of wit and fine feeling, the epic poems of Vergil and Klopstock fall into the noble, of Homer and Milton into the adventurous. The Metamorphoses of Ovid are grotesque; the fairy tales of French foolishness are the most miserbale grotesqueries ever hatched. Anacreontic poems are generally very close to the trifling" (Immanuel Kant, Observations on the Feeling of the Beautiful and Sublime, trans Goldthwait, 1960, pp. 56-57).