griper

plural gripers

1. One who gripes.
2. archaicAn oppressor or extortioner.

   When Southey's sackbut tunes the praise Of every Royal griper, Or any Minister, whose pipe Takes part in measures rotten ripe, While England pays the piper!

   1825, “Harmony at Congress”, in The Spirit of the Public Journals, page 533

   2 more examples

   She did Accept of our intended Present, which (she said) manifested our Love and Loyalty; most graciously affirming, That She was never any greedy Griper, or fast Holder; and what We did present, She would not hoard up; but Our Eyes should see the Bestowing of it.

   1601 December 1, John Croke, speaking before Parliament, in Proceedings in the Commons, 1601, British History Online

   […] there wanted not those who condemned his pride and hypocrisy, knowing Pandulphus to be a most greedy griper, as appeared by his unconscionable oppression in the bishopric of Norwich, which was afterwards bestowed upon him.

   1655, Thomas Fuller, Church History of Britain, published 1845, page 150