Definition of "on"
on1
/ɒn/
adjective
not comparable
(chiefly UK, informal, usually negative) Acceptable, appropriate.
(euphemistic) Menstruating.
preposition
(informal) In the possession of.
(especially Ireland) Indicating the person experiencing an emotion, cold, thirst, hunger, etc.
(obsolete, regional) of
(especially when numbers of combatants or competitors are specified) Against; in opposition to.
on2
/ɒn/
preposition
(UK dialectal, Scotland) Without.