" BID (Farewell) - BID / BADE - BIDDEN
BID (Offer amount) BID - BID
Do these words have any different? My dictionary says NO."
Check your dictionary again. Bid can be a verb or a noun, and they have completely different meanings.
"Another word Backslide.
BACKSLIDE - BACKSLID - BACKSLIDDEN / BACKSLID"
Here is the definition of backslide from the Oxford English Dictionary:
backslide: verb ( past -backslid ; past participle; backslid or backslidden).
To relapse into bad ways or error. Example 1: Converted vegetarians backslide to T-bones. | [as n. ] ( backsliding) Example 2: There would be no backsliding from the administration's sound policies.
"...because dictionaries says that "BACKSKID" Don't exist. Do it exist or don't? "
Are you certain you have not made a typo here? If yes, then "bacskid" is not in my dictionary either. I would tend to say that it does not exist in normal usage. It might be jargon in some professions (like stunt car drivers) but it has no relation to backslide.
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