zhttp://www.oed.com/dictionary/z_adj%3Ftab%3Dmeaning_and_use'Z, adj.
First published 1921; not fully revised

'Zadjective

  1. Phonetic spelling of 'S as a euphemistic shortening of God's in certain oaths: see zbloud at 'Sblood n. Forms, Z'Death at 'Sdeath int. Forms, zfoot at 'Sfoot int. Forms, Z'life n., &c.

'Z, adj. was first published in 1921; not fully revised.

'Z, adj. was last modified in September 2024.