• capital, essential, integral, intrinsic, intrinsical, material, relevant, significant, substantial, to matter
• in essence, intrinsically
• beside the mark, beside the point, beside the question, beyond the mark, immaterial, inconsequential, irrelevant, it has little effect, off the point, tenuous, to be of no consequence, unimportant
• body, burden, gist, guts, juice of sg, kernel of sg, prime mover, purport, quintessence
• inconsequence, irrelevance, irrelevancy
• difference of substance
• that is what he said or words to that effect