Degree
Extent, Level
noun, suffix
The extent degrees show to what degree or extent you're willing to take something.
This is a jukugo word, which usually means on'yomi readings from the kanji. If you know the readings of your kanji you'll know how to read this as well.
彼は実際は35歳だが、3歳児と同程度の知能水準しかない。
He is actually 35 years old, but has no more intelligence than a three year old kid.