Readings & Meanings:
to leave over
to be beyond (one's power)
People tend to fail if they do things hastily/if they don't allow enough time for things.
Because there was soup left over, I put the rest in the fridge.
I can't handle her selfishness/She's too selfish for me.
Yes, 余 is related to the grammatical あまり that we already know in such sentences as やる気があまりないねぇ. But remember these two things:
- Japanese people won't believe you that あまり and 余 are related
- don't ever use this kanji in place of あまり in this sense--あまり is always in hiragana.