ossify

verb (used with object), os·si·fied, os·si·fy·ing.

1. to convert into or cause to harden like bone.

verb (used without object), os·si·fied, os·si·fy·ing.

2. to become bone or harden like bone.
3. to become rigid or inflexible in habits, attitudes, opinions, etc.: a young man who began to ossify right after college.

verb -fies, -fying or -fied

1. to convert or be converted into bone
2. (intr) (of habits, attitudes, etc) to become inflexible

v.1713, “to turn into bone,” a back-formation from ossification, or else modeled on French ossifier (18c.) and formed from Latin os (genitive ossis) “bone” (see osseous) + -fy. Figurative sense is from 1858. Related: Ossified; ossifying. v.

1. To change into bone.