toughen

/ˈtʌf.ən/

动词

使坚韧；使变结实；加强
His time in the army certainly toughened him up.
军旅生涯确实使他变得更加坚强。
变困难
Amid toughening competition in the market, many firms are going out of business.
由于市场竞争愈趋激烈，许多公司只好歇业。