-ety

Etymology 1
Apparently an alteration of, as seen in , , etc.; equivalent to. The alteration of -d- to -t- is perhaps due to Scottish influence, where it is common for the past participle of Scots verbs to end in -et/-it rather than -ed as in English.

Alternatively, perhaps imitative of repeated action.

Etymology 2
Cognate of, ultimately from. See more at.