dis·cre·tion
[dih-skresh-uhn]

noun
1.the power or right to decide or act according to one’s own judgment; freedom of judgment or choice:  It is entirely within my discretion whether I will go or stay.

2.the quality of being discreet, especially with reference to one’s own actions or speech; prudence or decorum:  Throwing all discretion to the winds, he blurted out the truth.

Idiom
3. at discretion,  at one’s option or pleasure: They were allowed to work overtime at discretion.