Uncontaminated (4)
'uncontaminated' is the definition.
(similar in meaning)
This is all the clue.
(Other definitions for pure that I've seen before include "Chaste" , "Virgin" , "Unmixed with anything else" , "Not mixed with anything else" , "free of bad grammar" .)
'uncontaminated' is the definition.
(thesaurus)
This is the entire clue.
(Other definitions for sterile that I've seen before include "Like theatre" , "Aseptic or infertile" , "Antiseptic" , "Unable to have offspring" , "Not producing offspring" .)
'uncontaminated' is the definition.
(I've seen this before)
This is all the clue.
(Other definitions for clean that I've seen before include "Laundered" , "far from blue" , "Free from dirt; well defined" , "Unsullied" , "Clear (of drugs)" .)