apogee
Fulcrum
state
Pithy, terse.
ORIGMIorigin
gist
insist
Debate.
Can't think of an instance in which it would. "Main", is a comparative word which indicates by definition that it is one option among others. "My main man," means that this is the one who is the best among the others. The "main" point in an argument is the one that is most important.
argument?
dispute
specious
Argument, squabble or disunity.
Yes, the word 'argument' is a noun, a word for an angry disagreement between people; a word for a reason or set of reasons given in support of an idea, action or theory; a word for a thing.
main idea
main
justify, confirm, explain, condone, support, sustain