I. light ‧ weight 1 /ˈlaɪt-weɪt/ BrE AmE noun [countable]
1 . someone who has no importance or influence, or who does not have the ability to think deeply – used to show disapproval OPP heavyweight :
an intellectual lightweight
2 . a ↑ boxer who weighs less than 61.24 kilograms, and who is heavier than a ↑ featherweight but lighter than a ↑ welterweight
3 . someone or something of less than average weight
II. lightweight 2 BrE AmE adjective
1 . weighing less than average SYN light :
a torch made from lightweight plastic
2 . lightweight clothing or material is thin, so you can wear it in warm weather:
a lightweight jacket
3 . showing a lack of serious thought – used to show disapproval:
a lightweight novel