1. get out of bed on the wrong side - Verb
2. get out of bed on the wrong side - Phrase
get out of bed on the wrong side (third-person singular simple present gets out of bed on the wrong side, present participle getting out of bed on the wrong side, simple past got out of bed on the wrong side, past participle (UK) got out of bed on the wrong side or (US) gotten out of bed on the wrong side)
(idiomatic) To start the day in a bad mood for no apparent reason.
Our CO must have gotten out of bed on the wrong side, for he gave the whole company hell for their poor morale, dirty barracks, etc.