displaying strong feelings
ardent - enthusiastic
To be ‘ardent’ about somebody or something means to be highly passionate about them. It is characterized by an intensity of feeling that is typically expressed in fervent support or enthusiastic activity. However, you can also ardently oppose somebody or something. The word can be used in both a positive and negative context, as such zeal can lead to excessive or misguided behaviour.
My boss chose me to succeed him when he retires because I have always been an ardent disciple of his.
I have ardently defended that politician in the past, but back then I was too blinkered to see the truth about her.
Andrew has always been an ardent opponent of mine. His opposition to me seems to be based on bitterness and resentment.