剛

vajra (indestructible substance)

rigid body dynamics

superhuman strength

Vajrapani

extreme religious piety

tough at heart

Vajradhatu

Deva king (guardian god at a temple gate, holding a vajra)

diamond

Diamond Sutra

rigid body

very strong person

adamantine lustre (luster)

stiffness

shear modulus

shear modulus

firm and solid

Kalacakra

strength

black diamond

valor and decisiveness (valour)

gentle but firm

tough on the outside but soft at heart

being tough on the outside but soft at heart

gentle on the outside but tough on the inside

integrity

fast, heavy ball

blazing fastball

Shōmen Kongō

Hevajra

snubnosed eel (Simenchelys parasitica)

Vajradhara (vajra-wielding gods)

Diamond Wisdom Sutra

unaffected and sincere, with fortitude and vigor (vigour)

vajra bell

kongoban

emery (powder)

Vajrasekhara Sutra

unparalleled for valor

soft and fair goes far

Japanese bird cherry (Prunus grayana)

chilling (steel)

Vajrayaksa

firm and solid

Goju-ryu (karate school)

longhorn cowfish (Lactoria cornuta)

dauntless and decisive

bristle

firm and unyielding

hardness and softness

hardness and softness

pilgrim's staff

Mahavairocana (esp. in esoteric Buddhism)

strength

bravery

vajra (mystical weapon in Hinduism and Buddhism)

obstinacy

be reasonable, strong and do not give in

fortitude

bravery and cowardice

Diamond Perfection of Wisdom Sutra

Vajrasattva (bodhisattva in Mahayana and Vajrayana Buddhism)

Vajradhatu Mandala

vigour

macaw

green-winged macaw (Ara chloropterus)

obstinacy