Synonyms for Main (same or very similar meaning)
WordNet sense 1 (any very large body of (salt) water):
briny
WordNet sense 2 (in an extreme degree):
intense
WordNet sense 3 (most important element):
chief, primary, principal
WordNet sense 4 (of great significance or value):
important, of import
WordNet sense 5 ((of a clause) capable of standing syntactically alone as a complete sentence):
independent
From the ODE community, based on WordNet
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