borderline Antonyms

lodestone quintessence seat solved soul strong sure target umbilicus unconditioned vertebra viscera womb pith omphalos locus maximum medulla metacenter middle nave navel nidus nub nubble nucleolus nucleus bedrock cornerstone center of attention Central Point centre of attention epicenter epicentre forefront ground zero rallying point showpiece subpar central core ensured ill humour HQ nerve center nerve centre infielder heart and soul base hit bellybutton bench mark