Bittersweet

Bit·ter·sweet

Bittersweet

a.
  1. Sweet and then bitter or bitter and then sweet; esp. sweet with a bitter after taste; hence (Fig.), pleasant but painful. [Fig.]

Bittersweet

n.
  1. Anything which is bittersweet.
  2. A kind of apple so called.
  3. A climbing shrub, with oval coral-red berries (Solanum dulcamara); woody nightshade. The whole plant is poisonous, and has a taste at first sweetish and then bitter. The branches are the officinal dulcamara. (Bot.)