堅める
かためる
to hold a bow fully drawn, to wear for a specific purpose (armor, coat, etc.), to tie tightly, to fasten, to fortify, to reinforce, to support, to swear, to resolutely vow, to sincerely promise, to put together, to collect, to gather, to consolidate, to make secure, to stabilize, to settle down, to strengthen (belief, resolution, etc.), to establish (evidence), to harden, to freeze, to strengthen, to solidify, to make (a fist), to tramp down (snow, dirt)