I. ̷ ̷ˈ ̷ ̷ ̷ ̷_wənt noun
( -s )
Etymology: Latin substituent-, substituens, present participle of substituere to substitute
: something that is or may be substituted ; usually : an atom or group substituted for another or entering a molecule in place of some other part that is removed
aniline derivatives containing an alkyl or halogen substituent — Veterinary Bulletin
II. adjective
: functioning as a substituent