Are you thinking of "malice"? Maybe "animosity"? Or "loathing"?
Resentment.
Disgruntled means to be dissatisfied or unhappy with something, often due to feelings of unfair treatment or dissatisfaction with a situation. It typically implies a sense of displeasure or resentment.
The noun "animosity" means ill feelings or dislike.
A feeling of deep and bitter anger and ill-will
ill will or bitter resentment, hatred rancor is a noun
Grudgingly
It is to 'ail'
The noun 'bitterness' is an abstract noun as a word for a feeling of deep anger and ill-will; a feeling of resentment; a word for an emotion.The noun 'bitterness' is a concrete noun as a word for a harsh, unpleasant taste.
That is not a word. The actual word would be unsuitable. It means inappropriate.
Rancorous means resentful or bearing ill-will, generally negative feelings directed towards a specific person or thing.
You are full of Malice wishes. Malice means ill will.
If that could be "i," the answer is "ill."