Meaning of “extreme” - Learner’s Dictionary

extreme

adjective uk us /ɪkˈstriːm/
SERIOUS

B2 the most unusual or most serious possible:

In extreme cases, the disease can lead to blindness.
VERY LARGE

B2 very large in amount or degree:

extreme pain
extreme wealth
OPINIONS

having such strong opinions or beliefs that most people cannot agree with you:

extreme views
the extreme right
FURTHEST [ always before noun ]

at the furthest point of something:

in the extreme south of the island

(Definition of “extreme adjective” from the Cambridge Learner’s Dictionary © Cambridge University Press)