Definition from Wiktionary, the free dictionary
- (idiomatic) One who is friendly, helpful, or available only when it is advantageous or convenient to be so.
1871, Louisa May Alcott, chapter 14, in Little Men:
- She put little nosegays from her garden on his desk, and tried in every way to show that she was not a fair-weather friend, but faithful through evil as well as good repute.
- 1982, "Italy: New Image, New Influence," Time, 5 April:
- Pertini is being embraced as the leader of a staunch and increasingly important ally—a country that, as Reagan put it, "is no fair-weather friend but instead is an indispensable partner."