Definition of charley horse in US English:

charley horse

noun

North American
informal
  • A cramp or feeling of stiffness in an arm or leg.

    • ‘The pain from the hit was like a bad charley horse and lasted a good five minutes (and would linger another three days).’
    • ‘He's so tough that he played in the first round against the team despite a charley horse that caused significant swelling in his right thigh.’
    • ‘I sighed, feeling my knees beginning to hurt and a charley horse developing in my thigh.’
    • ‘‘I just got a charley horse,’ she told him casually.’
    • ‘And with the interruption of the body's normal nerve control, quadriplegics commonly suffer from muscle spasms - think of the worst charley horse you've ever had, one that threatens to strike at any time, in any situation.’

Origin

Late 19th century: of unknown origin.

Pronunciation

charley horse

/ˈtʃɑrli ˌhɔrs//ˈCHärlē ˌhôrs/