This is the 8402nd most frequent French word.
abuser
To misuse or take advantage of; to overindulge.
Here 'abuser' is used in the sense of 'overindulging' or 'excessively exploiting' something.
Il ne faut pas abuser des bonnes choses.
You should not overindulge in good things.
In this sentence, 'abuser' means 'to take advantage of' or 'betray someone's trust' negatively.
Elle a abusé de ma confiance.
She abused my trust.
Here 'abuser' implies misusing or exploiting power inappropriately.