Ridiculous myths about one workplace (6)
I believe the answer is:
smithy
'workplace' is the definition.
(smithy is a kind of workplace)
'ridiculous myths about one' is the wordplay.
'ridiculous' is an anagram indicator.
'about' is an insertion indicator.
'one' becomes 'I' (Roman numeral).
'myths' is an anagram of 'smthy'.
'smthy' going around 'i' is 'SMITHY'.
(Other definitions for smithy that I've seen before include "Workshop with anvil" , "Old forge" , "Workshop of metal worker" , "work area" , "Workplace for forging metal" .)