Health is not an adjective and therefore does not have comparative and superlative forms.Healthy, however, is an adjective, with the comparative form of healthier and the superlative form of healthiest.
Healthier is comparative of healthy.
Teapot is a noun and, as such, does not have a comparative degree.
"Less" is the comparative degree of little.
The comparative degree is bigger.
The comparative degree is wider.
Thriftier is the comparative degree of thrifty.
"Speed" is a noun and a verb and, as such, does not have a comparative degree. The comparative of the adjective speedy is speedier.
"Less" is the comparative degree of little. The superlative degree is least.
"Message" is a noun and (these days) a verb and, as such, does not have a comparative degree.
The comparative degree of "sad" is "sadder."
"More important" is the comparative degree of important.