Instructable and instructive are adjectives.
Instruct is a verb.
instructive
The verb form of instruction is "instruct."
The infinitive form of 'instruct' is simply 'to instruct'. All infinitives forms are preceded by 'to' in English.
No, it is not. It is the present tense, third person singular form of the verb to teach.
The adjective form of concept is conceptual.The adjective form of conception is conceptional.
The adjective form for the pronoun they is their.
The adjective form of concept is conceptual.The adjective form of conception is conceptional.
The Adjective form of Pathologist is Pathological.
The adjective form of improve is "improved."
One of these is likely your word: TRAIN - a vehicle, or to instruct TRYING - attempting, or an adjective meaning stressful