Collocation idioms refer to the association of roots or potential lexical meanings rather than actual words. It is important to learn collocations in language learning and communication. There are various types of collocations such as grammatical collocations, lexical collocations, and open collocations. Grammatical collocations include verb-preposition combinations, noun-preposition combinations, and adjective-preposition combinations. Lexical collocations consist of noun-verb combinations, adjective-noun combinations, and verb-noun combinations. Open collocations emphasize purpose or strong feelings in adverb-adjective combinations. Restricted collocations have specific structural patterns and limited commutability based on usage.