Definition of defatigation in US English:

defatigation

noun

Medicine
  • The fact or condition of being tired out or exhausted; fatigue, (in later use often) specifically mental fatigue.

Origin

Early 16th century; earliest use found in John Fisher (c1469–1535), bishop of Rochester, cardinal, and martyr. From classical Latin dēfatīgātiōn-, dēfatīgātiō physical or mental exhaustion, state of being worn out from dēfatīgāt-, past participial stem of dēfatīgāre + -iō.

Pronunciation

defatigation

/dɪˌfatɪˈɡeɪʃn/