noun, な adjective
You know that 完全 means "complete" or "perfect." So, a not "complete" or "perfect" is something that is incomplete or imperfect.
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. It also will help if you can read 完全.
What kind of love is imperfect?
Aren't incomplete things better than complete things, since they have a humanness about them?
The Tofugu softball team had an incomplete end to their season when the game they were winning was suspended due to rain.