crowning

Etymology 1

From Middle English crowninge, crounende, equivalent to crown + -ing.

verb

1. present participle and gerund of crown

adj

1. Supreme; of a surpassing quality or quantity.
   It seems that now [the Devil] was driving Alison hard. She had been remiss of late — fewer souls sent to hell, less zeal in quenching the Spirit, and, above all, the crowning offense that her bairn had communicated in Christ's kirk. 1902, John Buchan, The Outgoing of the Tide
   Friday night’s crowning victory at The Hawthorns was the 25th in 30 league matches since Antonio Conte’s decisive re-gearing of his team in September, the tactical switches that have coaxed such a thrilling run from this team of bolt-ons and upcycled squad players, most notably Victor Moses, who was dredged out of the laundry bin in the autumn to become a key part of the title surge. May 13, 2017, Barney Ronay, “Antonio Conte’s brilliance has turned Chelsea’s pop-up team into champions”, in the Guardian
   Lilian Greenwood has ranked boosting diversity and inclusivity among her crowning achievements from her two-year stint chairing the House of Commons Transport Select Committee. May 20 2020, “Network News: A legacy of greater diversity in transport”, in Rail, page 13

Etymology 2

From Middle English crouninge, crounynge, coroning, coronyng, equivalent to crown + -ing.

noun

1. A coronation.
   The crownings of the two successive monarchs were only a year apart.
2. The act of one who crowns (in various senses).
   There were outflankings and crownings of hills by numbers of thirteen and seventeen men, that made one hold one's breath. 1860, Fraser's Magazine, volume 61, page 711
3. (obstetrics) The stage of vaginal childbirth when the infant's head remains consistently visible at the vulva.
   When your baby’s head remains visible without slipping back in, it is known as crowning. 2012 April, Baby Crowning, American Pregnancy Association