On my libre writer the 'cut & paste' is greyed-out. How do I use it?

How do I get back my greyed out cut and paste in WRITER ?

May be your document is openend Read only - check Edit -> Edit Mode.

In some (not regular) cases LibreOffice denies to use the clipboard. Restart (of LO) often is the remedy.
Sometimes pasting by STRG+V can do, repeat it for some times and accidentally regular pasting works again. Don’t panic.

Cannot answer my question that is why I asked.

Any why do you post an answer to a question, which you cannot answer?