Names of word usages like “dead end”, “pitch black”

I’ve been wondering how there are some expressions made up of two words where the first word modifies the second one, but the first word is not necessarily an adjective that is commonly used to emphasize the meaning other words, for example: - Stark contrast - Pitch black

Are there any names related to this kind of language usage in English??

Solution 1:

Multi-word sequences, like "dead end", which have a figurative meaning beyond the individual words, "dead" and "end", are called idioms. In some cases, certain words are primarily known through their use in idiomatic expressions, e.g. few people recognize that "pitch" is a petroleum product when they say "pitch black" or that "drab" is a rough cloth when they say "olive drab".

If the meaning of an idiom is easily understood from its individual words, as in "diamond ring", it is considered a transparent idiom.

If it is harder to understand the meaning of the idiom from its individual words, as in "dead end" or "raw deal", it is considered an opaque idiom.