toughen

动词 toughen:

1. make tough or tougher

1. All this mountain climbing will toughen the boys up.
   这些爬山运动会把孩子们锻炼得身强体壮。
2. Mentally toughened; strong-minded.
   坚韧的有独到见解的; 意志坚强的
3. The company leader said that army life would toughen the recruits up.
   连长说军队生活可以使新兵锻炼得更坚强。