IPA: /ˈkwiːzɪnəs/
KK: /ˈkwiznəs/
The feeling of being sick to your stomach or having a strong sense of nausea.
After the roller coaster ride, I felt a wave of queasiness wash over me.
Queasiness is derived from the adjective 'queasy' (of uncertain origin, possibly from Old English 'cwēsan', meaning to be sick or nauseated) combined with the suffix '-ness' (meaning the state or condition of). The word 'queasiness' refers to the state of feeling nauseated or uneasy.
Think of feeling 'sick' ('cwēsan') and how that state ('-ness') makes you feel uneasy — that's what queasiness means.