umišljati

1. (+ da / sebi) to imagine; to fancy
   Stalno umišlja da je bolestan. — He keeps imagining that he's ill.
   Ne umišljaj sebi gluposti, sve je u redu. — Don't imagine nonsense, everything's fine.
2. (umišljati se) to be conceited; to think too much of oneself
   Otkad je dobio unapređenje, mnogo se umišlja. — Since his promotion he's become really conceited.

Usually used with a «da…» clause or with «sebi»: umišlja sebi da…