Idioms and Phrases with sweet on, be
sweet on, be
Enamored of, in love with, as in I think Barbara's sweet on Nick. This colloquial idiom was first recorded in 1740.
The American Heritage® Idioms Dictionary Copyright © 2002, 2001, 1995 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company.