堅

hard wood

robust; strong; tough

firm and solid; stout and durable

snow with a frozen crust on top; crusted snow

dogged perseverance; untiring patience

(the Christian sacrament of) confirmation

sophism; sophistry; quibbling

sound business

pachycephalosaur (any dinosaur of infraorder Pachycephalosauria)

Food, cooking

firm tofu; hard tofu

Rare term

firm and unyielding; rigid

Rare term

impregnable fortress; heavily guarded fort

underworld; netherworld

'ku' adjective (archaic)

hard; solid; tough

Esp. 固い and 堅い for wood, 硬い for metal and stone

hard; solid; tough

stiff; tight; wooden; unpolished (e.g. writing)

strong; firm (not viscous or easily moved)

safe; steady; honest; steadfast

obstinate; stubborn

bookish; formal; stuffy

to harden; to freeze; to strengthen; to solidify; to make (a fist); to tramp down (snow, dirt)

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 fortify; to reinforce; to support

In the form に身をかためる

to wear for a specific purpose (armor, coat, etc.)

to swear; to resolutely vow; to sincerely promise

to tie tightly; to fasten

to hold a bow fully drawn

nucleus; backbone; mainstay; key figure

Nouns which may take the genitive case particle 'no'

medium-level; mid-level; middle-ranking; midsize

main body (of troops); crack troops; select troops

Baseball

center field; centre field; center fielder; centre fielder

athlete competing in the middle-number match in a team competition, i.e. second in 3-on-3, third in 5-on-5 (kendo, judo, etc.)

Colloquial

prudish; strait-laced; boring; square

somewhat hard; somewhat firm; fairly hard; on the hard side

possessed of a strong sense of duty

sound; sure; safe; secure; trustworthy; reliable; solid

steady; firm

tight-lipped; able to keep a secret

skipjack tuna (Katsuwonus pelamis); oceanic bonito; victorfish

tight-lipped; able to keep a secret