||To put an end to something, to terminate or stymie.
||This will put the kybosh on everything.
This will put an end to everything (scheme, etc). (Murphy)
||Irish 'Caidhp B√°is' - the death cap, hence an end and note spelling. (√ď h-√Čaluithe)
Note Irish 'Caidhp' - a coif. (Dinneen)
and 'Caidhp B√°is' - death cap (botany). (√ď Domhnaill)
and 'Kibosh' - nonsense, put an end to, finally dispose of (19th century, origin unknown). (Concise Oxford Dictionary)
and 'Kybosh' - some sort of difficulty or 'fix'. "He put the kibosh on him - he defeated him". (Joyce)
'Kibosh' as above (military, First World War, Put the kibosh on the Kaiser). Perhaps Yiddish 'Kyebosh' or 'Kibosh' - eighteen pence. (Partridge)
and note 'Kybosh' - wages, money (Cornwall). (Wright)
and see "The woman had put the kibosh on things with her dastardly threats." (O'Mahony)