In grammar the comparative is the form of an adjective or adverb which denotes the degree or grade by which a person, thing, or other entity has a property or quality greater or less in extent than that of another. It is in fact, one of the two inflections, together with the superlative, an adjective or adverb can have.

The structure of a comparative consists normally of the positive form of the adjective or adverb, plus the suffix -er, or (especially in the case of longer words) the modifier "more" (or "less") before the adjective or adverb. The form is usually completed by "than" and the noun which is being compared, e.g. "he is taller than his father", or "the village is less picturesque than the town near by".

Those who pay heed to usage prescription frequently jar at the null comparative, a comparative in which the starting point for comparison is not stated. These comparisons are frequently found in advertising; for example, in assertions such as "Our burgers have more flavor!" (More flavor than what?), "Our picture tube is sharper!" (Sharper than what?), "50% more!" (50% more than what, exactly?), etc. Similar problems attend slogans such as "100% pure" (pure what, again?). In some cases it is easy to infer what the missing element in a null comparative is; in other cases the speaker/writer may have been deliberately vague in this regard.