a way of speaking to someone you love [= darling]:
Come here, sweetheart.
an informal way of speaking to a woman you do not know, which some women find offensive
3 American English
an agreement that is unfair because it gives an advantage to people who know each other well or to people who have a lot of influence:
Members of the council had arranged a sweetheart deal with CTS.
the person that you love:
They were childhood sweethearts.