強硬|きょうこうkyoukou[0]heiban (flat)

1. na-adjective, nounfirm; strong; unbending; unyielding; uncompromising; stubborn; tough; hard-line
   大統領だいとうりょうは強硬きょうこう路線ろせんをとった。↗

   The President took a hard line.

• Synonym断固だんこNeutralAn adverb for firm resolve, as in 「断固反対する」; it stresses determination, while 強硬 stresses an unyielding, hard-line attitude.
• Synonym強いつよいCasualRead 「こわい」, this means stiff, stubborn, or tired; dialectal and old-fashioned, rarely heard in everyday speech.
• Related強固きょうこNeutralMeans solid and stable, as in 「強固な意志」「強固な基盤」; stresses being hard to shake, not a hard-line stance.
• Related硬いかたいNeutralA common everyday word for physical hardness, also a stiff manner or inflexible mind; much broader in range than 強硬.
• Related強靭きょうじんWrittenA formal word for tough, resilient strength, as in 「強靭な肉体」; stresses tenacity and flexibility, not attitude.
• Related強烈きょうれつNeutralDescribes intense force or impact, as in 「強烈な印象」「強烈な反対」; 強硬 is reserved for an unyielding attitude.
• Related手ごわいてごわいNeutralDescribes an opponent too strong to handle easily, as in 「手ごわい相手」; stresses how tricky they are, not one's own stance.
• RelatedタフNeutralA loanword for being mentally or physically tough and hard to wear down; common in speech, with a positive ring.
• Related頑強がんきょうNeutralDescribes stubborn, unyielding resistance, as in 「頑強に抵抗する」; 強硬 describes the hard-line attitude itself.
• Related剛毅ごうきWrittenA formal word for firm, unbending willpower, mostly describing a person's character; bookish in flavor.
• Related果断かだんWrittenA formal noun for acting decisively, as in 「果断な処置」; stresses quick decision-making, not a hard line.
• RelatedハードNeutralA loanword for hard, tough, or punishing conditions, as in 「ハードな練習」; about severity, not one's stance.
• RelatedこわいCasualRead 「こわい」, this means stiff, stubborn, or tired; dialectal and old-fashioned, rarely heard in everyday speech.
• Related揺るぎないゆるぎないNeutralDescribes convictions that never waver, as in 「揺るぎない信念」; carries a positive nuance of steadfastness.
• Related手強いてづよいNeutralSame word as the previous entry, also written 「手強い」; can also mean a stern, unapproachable manner; 強硬 stresses holding one's position.
• Antonym軟弱なんじゃくNeutralThe opposite of 強硬: weak-willed, spineless, and quick to yield to others.
• Antonym穏健おんけんWrittenA formal word for moderate, temperate views, as in 「穏健派」; the direct opposite of a hard line.

Use 「強硬」 for a hard-line, uncompromising attitude, as in 「強硬な姿勢」 or 「強硬派」. For firm resolve pick 「断固」, for solid stability 「強固」, for a formidable opponent 「手ごわい」, and for stubborn resistance 「頑強」. 「穏健」 is the moderate opposite and 「軟弱」 the weak one.

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

1. 強つよく自分じぶんを主張しゅちょうして、考かんがえなどを曲まげないこと。また、そのようなさま。