1. [late 19C+] an attractive young woman.
2. [20C+] a beloved child.
3. [1910s+] (orig. US) a boy- or girlfriend.
4. [20C+] a term of address, not necessarily implying intimacy.
5. [1920s+] used ironically to mean an unpleasant person, e.g. He’s a real sweetie; also as adj., unpleasant.
6. [1930s+] a pleasant person.
7. [1960s–70s] an effeminate homosexual.
[1920s+] a general term of affection; a girlfriend.