Other forms: outnumbered, outnumbering, outnumbers
To outnumber is to be greater in number than another group. Outnumbered three to one, they outnumber us, heavily outnumbered.
It takes a ratio — outnumbered two to one — and it is the standard way of describing an imbalance in a battle, a workforce or a species count. Being outnumbered is not the same as being outmatched, which is about quality. Note the out- prefix meaning surpassing, as in outrun and outlast.
1verboutnumberTo be greater in number than another group.
“At the quiet protest, the police officers outnumbered the demonstrators.”
outnumber is an exceeding in number.
Proto-Indo-European
*nem-
Middle English
nombre
English
number
English, today
outnumber
From out- + number. number comes from Middle English nombre. Middle English number, nombre, numbre, noumbre, from Anglo-Norman noumbre, Old French nombre, from Latin numerus (“number”), ultimately from Proto-Indo-European nem- (“to distribute, to give, to take”). Compare stq Nummer, Nuumer, West Frisian nûmer, Dutch nummer (“number”), German Nummer (“number”), Danish nummer (“number”), Swedish nummer (“number”), Icelandic númer (“number”). ȝetæl and rime; more at tell, tale and rhyme. Distantly related (via Proto-Indo-European) to English nim (“to take, seize”) and its Germanic cognates (e.g. German nehmen), hence also to numb.
Etymology from Wiktionary, CC BY-SA