sunčanica

1. (of a medical condition) sunstroke
   Dobio je sunčanicu na plaži. — He got sunstroke at the beach.
   Stavi šešir da ne dobiješ sunčanicu. — Put on a hat so you don't get sunstroke.
2. (of an edible mushroom) parasol mushroom
   U šumi smo nabrali punu korpu sunčanica. — We picked a full basket of parasol mushrooms in the forest.

In the sense 'sunstroke' usually used with dobiti: dobiti sunčanicu.