(v): undergo a change; become different in essence; losing one's or its original nature
(v): make hard or harder
(v): undergo a change; become different in essence; losing one's or its original nature
(v): harden by reheating and cooling in oil
(v): make less severe or harsh or extreme
(v): make fit
(v): make tough or tougher
(v): cause to accept or become hardened to; habituate
(v): make psychologically or physically used (to something)