It can be used to describe both physical objects and ideas:
Physical objects:
* "The flimsy cardboard box wouldn't protect the delicate vase."
* "The tent was made of flimsy fabric and wouldn't stand up to strong winds."
* "Her flimsy excuse for missing work didn't convince her boss."
Ideas and arguments:
* "Their flimsy argument for the new policy didn't hold up under scrutiny."
* "The evidence presented was flimsy at best and did not prove their case."
Essentially, "flimsy" suggests something lacking in strength or substance, whether it's a material object or a logical argument.