Japanese synonyms and what is the difference

I’ve noticed some Japanese words mean the same thing but will be different Kanji or combinations of Kanji. The most recent are the two words 本当に and 全く。they seem to both mean really but is there a difference in when I would use these words? Are they actually synonyms?

Yes, they are different. One such is example is that 全く can be used to a verb conjugated in a negative form to mean something like ‘not at all’ or ‘never’ where as 本当に cannot. In that sense 全く is similar to 全然 which can also serve a similar purpose in negative verb to mean something like ‘not at all’.


‘I don’t know anything.’


‘I never watch TV.’

1 Like

本当に means truthfully, genuinely, in fact, etc.
全く means more like “entirely”, and it is often used in negative sentences like 全く分かりませんね “You really don’t get it, do you”. It can also be used by itself as an expression of exasperation like 全く “You’re so…”
I’m not sure if you can use 全く in positive sentences? Maybe you can, but I feel like 完全に would sound better.


You can. ‘全くその通り’ would be a way to express agreement with something, for example.

This Facebook post has a whole host of example for both affirmative and negative usages of 全く:

Also, just to make things fun I looked up 全く in my iPad dictionary and the second definition is:


Which I guess would encompass the affirmative usage of the word.

So to answer the original question, yes, they are synonyms but that doesn’t mean you can just swap one out for the other willy nilly.


So from what I’m understanding 全く can be used in negative or positive but 本当にcan only be used in the positive sense

The most common example to differentiate the two in day-to-day usage would be the way 本当に? is used on its own to just mean “Oh, really? Is that so? Truthfully?” in an exclamatory way. It’s often times an expression of surprise.

You don’t really hear anyone saying 全く in the same manner.


@jprspereira has a post about nuances for similar words. Have a gander!


This topic was automatically closed 365 days after the last reply. New replies are no longer allowed.