L
- lead with one's chin
- Boxing: To speak without caution, or to leave oneself unprotected. Refers to a boxer leaving his chin, a vulnerable point, unprotected. AHDI dates this usage to the "mid-1900s"; OED cites Erle Stanley Gardner in 1949.
- lightweight
- Boxing: (A person or thing) of little importance, consequence, intelligence or ability. In boxing, it is a weight division of boxers weighing no more than 135 pounds or 60.7 kg, or a boxer who fights in that division. OED cites boxing usage to 1823, figurative usage to 1885.
- low blow
- Boxing: An unscrupulous or unfair attack, action, or insult. Refers to an illegal blow aimed at the area below another boxer's waist or belt. AHDI cites this usage to about 1950. See hit below the belt, above.
Read more about this topic: List Of Sports Idioms