Rude plan in resort is characteristic of swinger (8)
I believe the answer is:
pendular
'characteristic of swinger' is the definition.
I know nothing about this answer so I can't tell whether this works.
'rude plan in resort' is the wordplay.
'in resort' indicates an anagram (letters get re-sorted).
'rude'+'plan'='rudeplan'
'rudeplan' with letters rearranged gives 'PENDULAR'.
'is' is the link.
Can you help me to learn more?
(Other definitions for pendular that I've seen before include "Like a grandfather clock" , "Hanging and swinging" .)