made tough by habitual exposure; "hardened fishermen"; "a peasant, dark, lean-faced, wind-inured"- Robert Lynd; "our successors may be graver, more inured and equable men"- V S Pritchett
If you are inured to something unpleasant, you have become used to it so that it no longer affects you. Doctors become inured to death
To apply in use; to train; to discipline; to use or accustom till use gives little or no pain or inconvenience; to harden; to habituate; to practice habitually
To take effect, or to benefit someone. In property law, the term means "to vest". For example, Jim buys a beach house that includes the right to travel across the neighbors property to get to the water. That right of way is said, cryptically, "to inure to the benefit of Jim"