to make (somebody) unfeeling or obdurate
to make (e.g. a plant) hardy
to make (something) hard
to become hard or hardened
induration /-ʹraysh(ə)n/ noun
indurative /inʹdyooərətiv/ adj
[Latin induratus, past part. of indurare, from in-2 + durare to harden, from durus hard]