資料來源 : pyDict

(使)變堅韌,(使)變頑固

資料來源 : Webster's Revised Unabridged Dictionary (1913)

Toughen \Tough"en\, v. i. & t. [imp. & p. p. {Toughened}; p. pr.
   & vb. n. {Toughening}.]
   To grow or make tough, or tougher.

資料來源 : WordNet®

toughen
     v : make tough or tougher; "This experience will toughen her"