Definition of iron-hearted in English:

iron-hearted

adjective

  • Extremely hard-hearted; unfeeling, pitiless; cruel.

Origin

Late 16th century; earliest use found in Thomas Becon (1512/13–1567), theologian and Church of England clergyman. From iron + hearted.

Pronunciation

iron-hearted

/ˌʌɪənˈhɑːtɪd/