ずっと

ずっと〈動どう詞し〉ているto have been doing something continuously
ずっと日本にほん語ごを勉べん強きょうしている。
I've been studying Japanese continuously.
〈物もの〉より〈物もの〉のほうがずっと〈形けい容よう詞し〉one thing is much more ~ than another
今こん年ねんは去きょ年ねんよりずっと寒さむい。
This year is much colder than last year.
〈場ば所しょ〉までずっと〈動どう詞し〉to go all the way to a place without stopping
駅えきまでずっと歩あるいた。
I walked all the way to the station.

Expressions

いつもN5sense 1
いつも means 'always' as in 'every single time', while ずっと stresses one unbroken stretch of duration.
もっとN5sense 2
もっと is a plain 'more', while ずっと in comparisons adds emphasis for a much larger gap.
まっすぐN5sense 4
まっすぐ focuses on the straightness of a path, while ずっと (in this sense) emphasizes going all the way without stopping.
常つねにN3sense 1
常に is a more formal, written-style word for constant continuation, while ずっと is the everyday spoken equivalent.

Show 4 more

はるかに sense 2
はるかに is a slightly more formal way to stress a big difference than ずっと, which is used the same way but more casually.
いつまでもN3
いつまでも stresses an endless or indefinite duration, while ずっと simply emphasizes continuous duration over a period without necessarily implying 'forever'.
始し終じゅうN2
ずっと is the everyday word for a long continuous stretch of time, while 始終 has a slightly more literary, 'throughout the whole thing' feel.
長ながらくN1
ずっと emphasizes continuity or comparison ('all along', 'by far'), whereas 長らく simply states a long duration without the continuous or comparative nuance.

どっとN2
ずっと looks and sounds similar to どっと but means 'continuously' or 'by far', not a sudden burst or rush.

ずっとUsage95%
Standard kana spelling.
ずーっとUsage4%
Emphatic lengthened form, common in casual speech and writing.
ずうっとUsage2%
search-only kana form
Search-only kana form; not a standard modern spelling.
ズットUsage<1%
ズーットUsage<1%

The origin is uncertain; it is a native Japanese adverb with no clear kanji etymology.