The word base is an adjective; based is the past tense of the verb 'base' (bases, based, basing).
It is not an adjective. It is a noun based on the adjective unfit.
Instinctively is an adverb. The adjective on which it is based is instinctive.
The noun colonialism is based on the adjective colonial. Colonial has other meanings but is based on the noun colony.
Microscopic is an adjective. The noun on which it is based is microscope.
Yes, it is an adjective based on the noun luck and the adjective lucky. The adverb form is luckily.
No, it is an adverb. It is based on the adjective special. (The word especial is practically archaic.)
Yes, indestructible is an adjective based on the verb destruct. It means unable to be destroyed.
Anxious is the adjective based on the noun (thing or condition) known as anxiety.
No. Eyesight is a noun. There is no particular adjective form, as most of the words are based on the word "vision."
arbitrary
No, it is an adjective. It is based on the noun rock.
Yes. It is an adjective based on the verb appear and the noun appearance. It refers to how something seems or seemed.