I had a bad night, and whenever I woke up I wondered if I knew this word and at times whether it was even a real word:
insouciant: Free of care or worry
Ironic, eh? The stem souciant was not in my big red dictionary. Though the quality of freedom from care or worry is insouciance. Then something really strange happened. I went to turn off my daughters alarm clock and forgot if the suffix had an a or an e in it. I've had the flu, though, and last night in particular a headache.