make tough or tougher;
"This experience will toughen her"
- This experience will toughen her.
- The company leader said that army life would toughen the recruits up.
- All this mountain climbing will toughen the boys up.
- toughen up （形势）变困难...
I hate my school..but Daddy was adamant. He said it would toughen me up.出自： C. Harkness
Old sandals, the leather stained and toughened by sea water.出自： P. D. James