facultative

 
Pronunciation: /ˈfak(ə)lˌtətɪv/

adjective

  • occurring optionally in response to circumstances rather than by nature: facultative adjustment in relation to competitive abilities
  • Biology capable of but not restricted to a particular function or mode of life: a facultative parasiteOften contrasted with obligate.

Derivatives

facultatively

adverb

Origin:

early 19th century: from French facultatif, -ive, from faculté (see faculty)