Theory
noun, suffix
You have reason behind your theory, making it a real theory (unlike those that don't have reason, I guess?).
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.
それ、ナゾ理論すぎるでしょ！
That theory sounds too unreasonable!
気にしない、気にしない。理論通りにいくことの方が少ないでしょ。
Don't worry about it, don't worry about it. You know, it's less likely to work out the way you theorize.
私、ドラマチックに伝えるのは得意なんですが、理論的に説明するのは苦手なんです。
I'm good at conveying things dramatically, but I struggle with explaining things theoretically.