Definition of Mondayitis in English:

Mondayitis

noun

informal, humorous
  • Reluctance to attend school or work, or a reduction in working efficiency, experienced on a Monday morning.

Pronunciation

Mondayitis

/ˌmʌndeɪˈʌɪtɪs/ /ˌmʌndɪˈʌɪtɪs/

Origin

Early 20th century; earliest use found in Weekly Advocate (Victoria, Texas). From Monday + -itis.