keyboard > abbreviations

hi there, i have a problem with the cancellation of the abbreviations i have created for the keyboard. i explain: i have created some abbreviations like the ones in the picture here

some of the words are no longer useful to me so i delete the ones that i do not need like this:

but after a few minutes the old words come back and appear again in the list.

FYI i am connected with the iCloud with other devices like iphone and ipad.

can you help me to delete the words i do not need once and forever? thanks a lot!!

cizi