忘 is a Logical Aggregate and Phonetic Compound at the same time, formed from two semantic indicators of 心 (literally means the heart or mind, feeling, intention) and 亡 (looking from the seal character of 忘, like a person hiding in a winding secret place 亾, originally means to run away or flee from home). 亡 (not wàng but wáng, due to the years of evolution of Chinese phonetics ) is also defined as its phonetic component.
忘记，不记得 forget; fail to remember
Lily explains 忘 like this:
Before trying to ease the character of 忘, Lily would like you to notice that in traditional Chinese view, a human being uses his heart to think and feel instead of the brain or mind. That's why 忘 has a semantic classifier of 心. There are times when we forget what we used to go great length to remember, and it's just like something slipping out of your mind, or, in a more Chinese perspective, running away from your heart.
People normally pay me for this and you are ginvig it away!
I might be beitnag a dead horse, but thank you for posting this!