cranky

the adjective 'cranky' emerged in english in the late 18th century, originally meaning 'sickly, in poor health'. its origin is uncertain but is likely connected to the obsolete english verb 'crank', meaning 'to bend or twist', which itself came from middle english 'cranke', meaning 'weak or shaky'. this sense of being unsound or unstable provides a clear semantic link to the modern meanings. from describing a person's physical infirmity, it evolved to describe an irritable, ill-tempered mental state, and later, by metaphorical extension, to describe a malfunctioning, unstable machine or mechanism.

the word 'cranky' is a simplex word. it is not productively formed from modern english morphemes, so a meaningful segmentation into substrings that carry distinct senses is not possible.