re: What’s the OT’s definition of love?

Where True love exists, difficult things are easy.
Where true love does not exist, easy things are difficult.

You can't give what you ain't got. You receive true love from God the Father.
Love is normally taught to a child by their parents. Prayer nourishes what the parents teach.
Some parents teach a twisted form of love, and the child grows up into an adult and has to unlearn this distorted type of love, so they can learn true love.

Where should one go to learn true love? Confession. When one receives forgiveness from God, one receives peace and mercy. As one continues to receive forgiveness, they are being taught how to forgive. Now they can forgive others in a more loving, generous, and joyful way. Forgiving can be difficult, but if one has true love, difficult things are easy.