An onomatopoeic adverb expressing plopping or flumping down heavily (e.g., sitting or putting something down with weight).
彼は疲れてソファにどっかり座った。
He was tired and plopped down heavily onto the sofa.
買い物袋を床にどっかり置いたら、猫が驚いて逃げた。
When I plunked the shopping bag down on the floor, the cat got startled and ran away.
彼女は動じずにどっかり構えて、話を最後まで聞いた。
She sat firmly and calmly, listening to the whole story.