adamantyl

As a noun adamantyl

is (organic chemistry) the univalent radical derived from adamantane.

As an adverb adamantly is

in an immovable or inflexible manner.

As nouns the difference between adamantane and adamantyl

is that adamantane is a polycyclic hydrocarbon, C₁₀H₁₆, having a cagelike structure similar to a portion of the diamond lattice; any of its derivatives while adamantyl is the univalent radical derived from adamantane.

In organic chemistry terms the difference between radical and adamantyl

is that radical is a free radical while adamantyl is the univalent radical derived from adamantane.

As nouns the difference between radical and adamantyl

is that radical is a member of the most progressive wing of the Liberal Party; someone favouring social reform (but generally stopping short of socialism) while adamantyl is the univalent radical derived from adamantane.

As an adjective radical

is favoring fundamental change, or change at the root cause of a matter.