How to say "hard-headed" in Japanese

• 冷徹れいてつCommon
  na-adjective, nounThe common word for the positive sense: cool-headed and level-headed, clear-sighted and unsentimental rather than stubborn. Fits a calm, rational decision-maker who weighs the facts without letting emotion interfere.
• 金槌頭かなづちあたま
  nounA vivid image — literally a head as hard as a hammer — for the stubborn sense: someone who will not listen or change their mind. Less common, and purely about obstinacy, not clear thinking.
• 固陋頑迷ころうがんめい
  noun, na-adjectiveA four-character idiom for the stubborn sense at its most disapproving: obstinate, pigheaded, clinging to one's own opinions. Less common, and strongly critical — seldom a neutral way to say 'hard-headed'.

冷徹, the common word, covers the positive clear-headed sense; for the stubborn sense, 金槌頭 is a vivid word for someone who will not listen, while 固陋頑迷 is a strongly critical four-character idiom.

Usage comparisons are AI-assisted and cross-checked by multiple models; for study reference only

• 冷徹れいてつcool-headed
• 金槌頭かなづちあたまhard-headed
• 固陋頑迷ころうがんめいobstinate