facultative

adjective

fac·​ul·​ta·​tive ˈfa-kəl-ˌtā-tiv 

 British  -tə-tiv

1

a

: of or relating to the grant of permission, authority, or privilege

facultative legislation

b

: optional

2

: of or relating to a mental faculty

3

a

: taking place under some conditions but not under others

facultative diapause

b

: exhibiting an indicated lifestyle under some environmental conditions but not under others

facultative anaerobes

facultatively adverb

Examples of facultative in a Sentence

Recent Examples on the Web

For the cancer patients, their gut showed a lower amount of beneficial bacteria and a higher amount of facultative pathogens. —Stephanie Edwards, Discover Magazine, 13 June 2025

After heading several facultative roles at the company, Elamin serves as the head of facultative for Aon Reinsurance Solutions for the Middle East, Africa and Turkey. —Mckinley Franklin, People.com, 8 Jan. 2025

Unlike the Queensland lungfish, which is a facultative air-breather, the South American lungfish must breathe air to survive. —Scott Travers, Forbes, 15 Sep. 2024

This is all speculative, but the hypothesis that Dudgeon is playing with is that, for some vertebrates, facultative parthenogenesis might be like the evolutionary equivalent of a Hail Mary pass. —Byrd Pinkerton, Vox, 12 June 2024

This occurred through facultative parthenogenesis, a form of asexual reproduction. —Kyle Melnick, Washington Post, 9 June 2023

Word History

Etymology

borrowed from French & New Latin; French facultatif, borrowed from New Latin facultātīvus, from Medieval Latin facultāt-, facultās "ability, power, authority, privilege, right" (Latin, "ability, power") + Latin -īvus -ive — more at faculty

First Known Use

1820, in the meaning defined at sense 1a

Rhymes for facultative

• allocative
• appellative
• commutative
• connotative
• copulative
• degradative
• dissipative
• educative
• exudative
• imitative
• infiltrative
• innovative

Medical Definition

facultative

adjective

fac·​ul·​ta·​tive ˈfak-əl-ˌtāt-iv 

1

: taking place under some conditions but not under others

facultative parasitism

2

: exhibiting an indicated lifestyle under some environmental conditions but not under others

facultative anaerobes

facultatively adverb