How to tell them apart
いわゆる modifies a noun to label something by its widely recognized name, as in いわゆる「バブル経済」, pointing to an established term. 言わば is an adverb offering a figurative comparison, as in 言わばウォーミングアップ, where the speaker chooses a metaphor rather than citing a common label. Swapping them fails because いわゆる cannot introduce a metaphor and 言わば cannot directly modify a noun phrase.
- いわゆる Use いわゆる when attaching a widely recognized label to a noun.
- 言わば Use 言わば when offering a figurative comparison or metaphor for a situation.
| Grammar point | Meaning | JLPT level |
|---|---|---|
| いわゆる iwayuru | what people call something; commonly known as | N2 |
| 言わば waba | In a manner of speaking; figuratively; kind of | N2 |
いわゆる iwayuru
what people call something; commonly known as
いわゆる is a pre-noun modifier meaning the thing named is known by that label to people in general, often with a slight nuance that the label may not be exact. It comes directly before a noun, as in いわゆる天才 or いわゆる温室効果, and is used in both written and spoken Japanese.
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彼は偉大な学者ではあるが、いわゆる常識に欠けている。
He is a great scholar, but lacks what is called common sense.
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彼はいわゆる天才ではない。むしろ彼は努力家なのだ。
He is not what is called a genius. Rather, he is a hard worker.
言わば waba
In a manner of speaking; figuratively; kind of
言わば is an adverb meaning "so to speak" or "as it were." It is placed before the phrase or clause it qualifies, typically a statement comparing something to something else, often with ような or だ. It appears in both casual and formal sentences and simply signals that the speaker is describing something figuratively.
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彼は、言わば、陸に上がった魚のようなものだ。
He is, so to speak, a fish out of water.
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彼は、言わば、水の外にいる魚のようなものだ。
He is, so to speak, a fish out of water.
いわゆる and 言わば are both JLPT N2 grammar points that Japanese learners often mix up. This page compares them side by side on meanings, usage and example sentences, so you can tell them apart.