hygienic

adj

1. Pertaining to hygiene; clean, sanitary, free of disease.
2. (slang)Whose expansion is guaranteed not to cause the accidental capture of identifiers.

   “Of course, anyone with a Scheme background is probably howling at this point because they have a hygienic macro system that makes unintended variable capture impossible. Allowing variable capture when we really, really want it makes Clojure's macro system technically more dangerous than hygienic systems.”