すぐさま・直ぐさま・直ぐ様・すぐ様sugusama[1]atamadaka (head-high)

1. adverbimmediately; promptly
   すぐさま彼かれの申し出もうしでにとびついた。↗

   I readily grasped at his proposal.

• Synonym早速さっそくNeutralFor getting started on something right away, as in 「早速始めよう」; the emphasis is on launching into action at once.
• Synonym早々そうそうNeutralCovers 'just after ...', as in 「開店早々」, and also doing something early or in haste.
• Synonym直ちにただちにFormalFormal, with a strong sense of urgency, as in 「直ちに避難してください」; the word for formal directives.
• SynonymすぐにNeutralThe everyday default for 'right away', as in 「すぐに行きます」; more casual than 「すぐさま」.
• Synonym即刻そっこくFormalFormal and forceful, as in 「即刻退場」; carries a stern, commanding tone.
• Synonym即座にそくざにNeutralFor responding on the spot without a moment's delay, as in 「即座に答える」.
• SynonymとっさにNeutralFor split-second, reflexive action in an emergency, as in 「咄嗟に身をかわす」; stresses instinctive reaction.
• Synonym即時そくじWrittenWritten and often technical, meaning 'in real time', as in 「即時反映」 or 「即時に対応する」.
• SynonymすかさずNeutralActing at once without letting the moment slip, as in 「すかさず反論する」.
• SynonymさっさとCasualColloquial; doing something briskly or telling someone to hurry, as in 「さっさと帰れ」; often carries an urging tone.
• Synonymいち早くいちはやくNeutralMeans being first, ahead of everyone else, as in 「いち早く知らせる」.
• SynonymたちまちNeutralDescribes a state changing in an instant, as in 「たちまち売り切れ」; the focus is on how fast the change happens.
• Synonym至急しきゅうFormalFormal, stressing urgency, as in 「至急ご連絡ください」; typical of business and official requests.
• SynonymすぐNeutralThe most common word for 'soon, right away'; also means very close by, as in 「すぐそこ」.
• SynonymたちどころにWrittenWritten style; means on the spot, at once, as in 「たちどころに解決」.
• Synonym直様じきさまWrittenRead 「じきさま」 — a different reading from 「すぐさま」; an old-fashioned word for 'at once', rarely used today.
• Synonym猶予なくゆうよなくWrittenWritten style; stresses allowing no grace period or buffer, e.g. when handling complaints.
• Synonym時を移さずときをうつさずWrittenA solemn written set phrase for doing something at once, as in 「時を移さず実行する」.
• Related迅速じんそくWrittenA written-style noun/na-adjective for swiftness, as in 「迅速な対応」; not used alone as an adverb.
• Related早くはやくNeutralCovers both 'quickly' and 'early/soon', as in 「早く来て」; the focus is on speed or earliness rather than immediacy.
• RelatedやにわにWrittenWritten and dated; means acting at once but abruptly, with a hint of suddenness; not used in daily speech.
• Related早いとこはやいとこCasualColloquial, with a casual, nudging feel, as in 「早いとこ片付けよう」; 'let's get this done quickly'.
• Related一も二もなくいちもにもなくNeutralA set phrase meaning unhesitatingly, as in 「一も二もなく賛成」; stresses lack of hesitation, not speed.
• Related早うはようCasualA dialect form in Kansai and elsewhere, common in local speech; equivalent to standard 「早く」, which you should use in standard contexts.
• Related疾く疾くとくとくWrittenArchaic for 'swiftly'; now mostly in classics or archaizing, quoted expressions; say 「早く」 in everyday speech.
• Antonym後であとでNeutralAntonym: doing things later rather than acting at once like 「すぐさま」.
• Antonym遅れてNeutralAntonym: being delayed or late, the opposite of the immediacy of 「すぐさま」.

For everyday 'right away', say 「すぐに」. Use 「すぐさま」 when you act at once right after something happens, as in 「すぐさま駆けつける」. For formal directives, choose 「直ちに」. Other shades: 「即座に」 for on-the-spot replies, 「咄嗟に」 for reflexes, 「即刻」 for forceful formal orders, 「早速」 for getting started, 「いち早く」 for beating others to it, 「たちまち」 for rapid change, and written 「立ちどころに」 or 「時を移さず」.

Usage comparisons are AI-assisted and cross-checked by multiple models; for study reference only

1. すぐに。ただちに。