Letters that make toughen
o, e, g, n, h, t, u are letters that make 'toughen'
toughens is a word created by adding a letter to 'toughen'
1 possible definitions for 'toughen'
Under this definition, toughen is a verb and has the following properties:
'toughen' can be a type of strengthen.
"This experience will toughen her"