Star put in jeopardy beneath a wobbly set (8)
I believe the answer is:
asterisk
'star' is the definition.
(synonyms)
'in jeopardy beneath a wobbly set' is the wordplay.
'in' indicates putting letters inside.
'jeopardy' becomes 'risk' (synonyms).
'beneath' is a charade indicator (letters next to each other) (in a down clue, some letters go below others).
'wobbly' is an anagram indicator (I've seen this in other clues).
'risk' put after 'a' is 'arisk'.
'set' with letters rearranged gives 'ste'.
'arisk' placed around 'ste' is 'ASTERISK'.
'put' acts as a link.
(Other definitions for asterisk that I've seen before include "Footnote marker" , "Star on a page" , "Textual reference symbol" , "Star of typography" , "Star-shape on the page" .)