an interest or concern that occupies a large part of someone's time and effort
But up to the day he first saw her face his ruling passion had been the love of glory.
It may be said of him that gratitude became the ruling passion of his heart.
To him the Union stood first and the State second, and to make the Union great and strong became a ruling passion in his life.
The ruling passion of the villain's life was his love for his daughter.
Occasions were eagerly sought for to give employment to the ruling passion.
Jealousy of the royal power, however, was still a ruling passion.
The ruling passion of this lady was thrift; her next, good housewifery.
Well, it is something to have found out that vanity is the ruling passion.
What "the ruling passion" may be among men, I cannot presume to consider.
Everything must bend before the ruling passion, “to better his condition.”