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backside basement basis base bedrock bed behind boat bum butting buttocks butt butt butted in craft crafts depend depended depth derriere/derrière derriere essence fanny footing foot found foundation foundations fundament fundamental ground hinging on hinges 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 substances substance substratum support supports tail under underneath underneath underlying underside valleys valley vessel zero