Something that is delicate and fragile can be described as frail. Grandma's favorite vase is probably too frail to use for football practice; some of us have learned that the hard way.
Frail can also be used to describe a person's physical condition: "When I broke my grandmother's vase, she yelled in a voice so loud that it was hard to believe it was coming from her small, frail frame." Another way to use frail is in reference to a person's emotional state. As the poet Sylvia Plath astutely observed, "How frail the human heart must be."