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backside basement basis base bed bedrock behind boat bum butted in butting buttocks butt butt craft crafts depend depended depth derriere derriere/derrière essence fanny footing foot foundation found foundations fundament fundamental ground hinges on hinging on hinge on hollow inferior keister/keester least lesser low lowest marrow meat and potatoes minimum more primary most fundamental most inferior most primary nadir pedestal posterior primary/prime primest quintessence radical rear rest rest reverse rock bottom root rudiment seat seat setbacks side slump soul souls stuff substance substances substratum support supports tail under underneath underneath underlying underside valleys valley vessel zero