major league (plural major leagues)

1. An association of sports teams which plays at the highest skill level of its sport, especially Major League Baseball.
2. (usually, in plural or attributive) The highest level of competition in a field of endeavor.

   You can't be so casual. You're in the major leagues now.

• (all senses) big league, majors, big time
• (association) superleague, elite league

major league

1. (sports) Of or pertaining to a major sports league; belonging to the professional level of a sport, such as US baseball.
2. (by extension) Analogous in importance to a major league sports team.

   That rock band is really major league.

   Calatrava is a major league architect.

3. (figurative) Serious, high-level; significant

   The company made a major league effort to get the contract.

   Bill accidentally faxed sensitive documents to our competitors, and such a major league mess-up could only be dealt with by firing Bill.

   • 1991, Bret Easton Ellis, American Psycho, London: Picador, →ISBN, page 148 ↗:

     […] I'm experiencing a major-league anxiety attack, searching my pockets for Valium, Xanax, a leftover Halcion, anything, and all I find are three faded Nuprin in a Gucci pill-box, so I pop all three into my mouth and swallow them down with a Diet Pepsi and I couldn’t tell you where it came from if my life depended on it.