Regex Pattern for specific word

The Rules:

• if the the word 'ore' as a starter, it's match 'rose' or 'zero' but not contains substring 'ore' like 'sore'.
• if the word 'opts' as starter, the 'posts', 'stops', 'spot' , 'tops' but not contains substring 'opts'
• we can add one letter before or after the word but not both like 'opts' could be 'stops'

thank you