Adjective first class has 1 sense
- excellent, first-class, fantabulous - of the highest quality; "made an excellent speech"; "the school has excellent teachers"; "a first-class mind"
Antonym: inferior (indirect, via superior)
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Adverbial first class has 1 sense
- first-class - by first-class conveyance; with first-class accommodations; "we always travel first class"
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Noun first class has 3 senses
- first class - the highest rank in a classification
--1 is a kind of superiority, high quality
- first class, 1st class, first-class mail, 1st-class mail, priority mail - mail that includes letters and postcards and packages sealed against inspection
--2 is a kind of mail
--2 has particulars: correspondence
- first class - the most expensive accommodations on a ship or train or plane
--3 is a kind of accommodation
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