adverb taking the 'to' particle, adverb
dejectedly; crestfallen; sorrowfully
Describes leaving or moving away in a dispirited, downcast manner, often after a disappointment or failure. Typically used with verbs of motion like 去る or 帰る.
彼は叱られて、すごすごと部屋を出ていった。
He was scolded and left the room dejectedly.
不合格の知らせに
Upon hearing the news of his failure, he went home crestfallen.
しょんぼり emphasizes a lingering state of sadness or loneliness, often with a visible drooping posture, while すごすご focuses on the action of leaving or retreating in a dejected manner.
がっかり is a more general expression of disappointment, not necessarily tied to physical movement. すごすご specifically describes a dispirited departure.
The origin is uncertain. It is an onomatopoeic or mimetic adverb that phonetically suggests a subdued, shuffling manner.