しっかりした (translations)→ assured brave crack dependable disciplined firm hardheaded heavy purposeful solid steadily steady strong
堅い (translations)→ promise prude solemn straight unshakable
不変の (translations)→ always idempotent immutable invariant
分解できない (translations)→ irresolvable unanalyzable
変わらない (translations)→ as unchanging unflagging
