spekulacija

1. speculation; conjecture
   To su samo spekulacije, niko ništa ne zna sigurno. — That's just speculation, nobody knows anything for sure.
   U medijima ima mnogo spekulacija o ostavci ministra. — There is a lot of speculation in the media about the minister's resignation.
2. (in economics) speculation
   Cene stanova rastu zbog spekulacije. — Apartment prices are rising because of speculation.

In the first sense the word is often used in the plural: spekulacije.