Cover one undressed catching cold oddly (7)
I believe the answer is:
include
'cover' is the definition.
(thesaurus)
'one undressed catching cold oddly' is the wordplay.
'one' becomes 'i' (Roman numeral).
'undressed' becomes 'nude' (I've seen this before).
'catching' means one lot of letters goes inside another.
'oddly' indicates alternate letters.
The alternate letters of 'cold' are 'cl'.
'nude' going around 'cl' is 'nclude'.
'i'+'nclude'='INCLUDE'
(Other definitions for include that I've seen before include "Have within" , "Feature" , "Add as part of something else" , "Throw in" , "Consider as part of something" .)