I found this dime today that was abnormally thick on one side of the coin and perfectly fine on the other. took two pictures of the error coin with a normal one for comparison.
It might be finning, but not necessarily. A pic of the obv & rev will show if it is or isn't. It could also be a defective planchet - thin on one side & thick on the other.
Most likely it is a case of finning. Tapered planchet errors are very rare on clad dimes. Still, you should weigh it to the nearest 1/10 of a gram to see if it is abnormally light or heavy.
