n.

1. 心上人，恋人，情人[C]
   She was John's childhood sweetheart.

   她是约翰儿时的心上人。

2. 【口】甜心（用来称呼心爱的人或家人；女人口语上表示友善的称呼）
   What can I get you, sweetheart?

   （最常出于女店员或餐馆女侍之口）我能为你拿点什么，甜心？

vi.

1. 恋爱
   Boys of your age ought to be sweethearting.

   你这个年纪的男孩该是求爱的时候了。

vt.

1. 向……求爱；与……恋爱

n.

1. a person that one is in love with.
   ▸used as a term of endearment or affectionate form of address.
2. [as modifier] informal denoting an arrangement reached privately by two sides in their own interests:
   a sweetheart deal.