Bespoke is an adjective for anything commissioned to a particular specification. It may be altered or tailored to the customs, tastes, or usage of an individual purchaser.
Synonyms include "custom-made", "made to order", and "made to measure"
Antonyms include "off-the-shelf" and "ready-to-wear"
The slang term "modding" is different but somewhat related; it refers to personalization of an item after manufacture
The word bespoke is derived from the verb to bespeak, meaning to "speak for something". The particular meaning of the verb form is first cited from 1583 and given in the Oxford English Dictionary: "to speak for, to arrange for, engage beforehand: to ‘order’ (goods)”. The adjective "bespoken" means “ordered, commissioned, arranged for” and is first cited from 1607.
The term is generally more prevalent in British English; for example, StyleRocks "bespoke jewellery".American English tends to use the word "custom" instead, as in custom car, custom motorcycle, etc. Nevertheless, "bespoke" has seen increased usage in American English during the 21st century, particularly in the phrase "bespoke suit."