Abbreviation of Thinspiration.
Formed after the words 'thin' and 'inspiration', the thinspiration is the motivation obtained of certain kind of images and quotes to stay thin or lose weight.
It became popular in pro eating disorder sites, where the thinspiration consist of photos of extremely skinny girls and quotes that promote starvation.
But it has also a widely extended healthy meaning where the photos are of thin or fit girls, of low calories food, exercises and quotes that motivates to stay thin in a healthy way.
Those thinspo pictures are helping me to stay away from the fridge.
Her favorite thinspo quote is "Nothing tastes as good as thin feels"