Time out for parasite (4)
'parasite' is the definition.
'time out' is the wordplay.
'out' indicates an anagram (out can mean wrong or inaccurate).
'time' with letters rearranged gives 'MITE'.
'for' is the link.
(Other definitions for mite that I've seen before include "Arachnid; small child", "The widow's small donation", "Very small creature or child", "Child; a small amount", "The widow's contribution, just in time".)