まず・先ずmazu[1]atamadaka (head-high)

1. adverbfirst (of all); firstly; to begin with; before anything else
   まず第だい一いちに私はジムを訪たずねなければならない。↗

   First of all, I have to call on Jim.
2. adverbprobably; most likely; almost certainly; virtually
   あのチームは、あるとしても、まず優勝ゆうしょうの望のぞみはない。↗

   That team has little, if any, chance of winning.
3. adverbmore or less (satisfactory); on the whole; reasonably
4. adverbanyway; at any rate; for now (at least); for the time being

• Synonym第一だいいちNeutralA noun for first place or top importance, as in 「安全第一」; it ranks things rather than marking the first action, unlike the adverb 「まず」.
• Synonym最初さいしょNeutralA noun for the very start of something, as in 「最初の日」; 「まず」 is an adverb for doing something first, so they fill different roles.
• SynonymはじめにNeutralCovers both the start of a speech or text and the first step in an activity, as in 「初めに手を洗う」; in the step-by-step sense it works like 「まず」.
• Synonym真っ先にまっさきにNeutralEmphasizes being the very first, ahead of everyone or everything else, as in 「真っ先に駆けつける」 or 「真っ先に思い浮かぶ」.
• RelatedとりあえずCasualColloquial: for now, as a temporary first move, as in 「とりあえずビール」; the provisional nuance sets it apart from 「まず」.
• Related何はさておきなにはさておきCasualColloquial: do this first regardless of everything else, stressing its priority, as in 「何はさておき乾杯」.
• Related何はともあれなにはともあれCasualColloquial: anyway, in any case, as in 「何はともあれ無事でよかった」; it sets other matters aside rather than marking a first step.
• RelatedまずはNeutral「まず」 plus 「は」, spotlighting the first thing to do, as in 「まずは落ち着け」 or 「まずはお礼まで」; otherwise used the same way.
• Antonym次につぎにNeutralThe counterpart of 「まず」: marks what comes next, the second step in a sequence.
• Antonym最後にNeutralThe counterpart of 「まず」: marks the end or final point, as in 「最後に一言」.

「まず」 is the default for 'first (of all)'. Use 「まずは」 to stress the first thing to do, 「とりあえず」 for a tentative 'for now', 「何はさておき」 for going ahead regardless of everything else, and 「真っ先に」 for being first ahead of the rest. For the next step use 「次に」, and for the end 「最後に」.

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

1. 最初さいしょに。第だい一いちに。
2. ともかく。
3. おおよそ。大体だいたい。多分たぶん。