I. ˈswēt-ˌhärt noun
Date: 14th century
1. : darling
2. : one who is loved
3. : a generally likable person
4. : a remarkable one of its kind
II. adjective
Date: 1942
: of or relating to an agreement between an employer and a labor union official arranged privately for their benefit usually at the expense of the workers
a sweetheart contract
broadly : arranged in private for the benefit of a few at the expense of many
a sweetheart deal