That moment that a greek word is defined by one (or ...five) greek word(s)...

Disaster

From Greek ‘dis’ ('δυς' meaning bad) and ‘aster’ ('αστήρ' meaning star).

Bad stars and other celestial omens were thought to be responsible for any calamity that occurred during the Hellenistic period, both naturally-occurring and very much man-made.

Catastrophe

From Greek 'kata' (meaning against) and 'strophē ' (meaning ‘turning’) i.e. sudden turn