Great warmth and earnestness of feeling. (Dictionary.com)
Intense and passionate feeling. (Oxford Dictionaries)
Strong and sincere beliefs. (Cambridge Dictionary)
Fervour for something is a very strong feeling for or belief in it. (Collins Dictionary)
Naked holy men add fervour to Nepal Hindu fest.
Holi festival of colours celebrated with fervour.
Colour powders produced traditionally sold in the streets of the Holi festival of colours.