mau vs mer, What's the Difference?

Which to use

“mau” is an adjective and “mer” is a noun - they look or sound alike but fill different roles in a sentence.

#1,936
“mau” frequency rank: #22,090
“mer” frequency rank: 24026
confusion score

Side-by-Side Comparison

Feature	mau	mer
Definition	que não é de boa qualidade, ruim	mar

Where the eye mixes mau and mer

Muted = shared; highlighted = the visual trap. They share 1 letter in sequence.

3 ch

mau

3 ch

mer

Look-alike desk: mau vs mer

These two trip readers on the page rather than in the ear: mau is /ˈmaw/ while mer is /mɛʁ/. Spoken aloud the problem disappears. In writing it persists, because they share most of their letters but differ in 2 positions, and the parts of speech differ too (adjective vs noun), which is usually the fastest check. Our composite confusion score for this pair is 24026, derived from the frequency rank of both members and their visual similarity.

mau is recorded at frequency rank #1,936, classified as anadj, pronounced /ˈmaw/. mer is at rank #22,090, tagged as anoun, pronounced /mɛʁ/.

Glosses for this pair are partially populated in our dataset, but the full side-by-side definitions above should still guide you to the right choice.

With a confusion score of 24026, this pair ranks #45,684 of 75,631 scored Portuguese confusable pairs - roughly mid-pack for confusability.

Orthographic DNA of mau vs mer

Shared letters: m. Private to "mau": au. Private to "mer": er.

"mau" · 3 letters · shape CVV · "mer" · 3 letters · shape CVC

Frequently Asked Questions

Can "mau" and "mer" be used interchangeably?

No - they are not even the same part of speech. "mau" is an adjective and "mer" a noun, so a sentence built for one is usually ungrammatical with the other.

In ordinary Portuguese text, does "mau" or "mer" show up more?

"mau" is the more common of the two: it sits at frequency rank #1,936 in our Portuguese list, against #22,090 for "mer". That is a wide gap, so in ordinary text the rarer spelling is the one worth double-checking.

After this comparison

Eye-level mix-up between "mau" and "mer" is sorted above. Next: full entries or other pairs that share a letter shape.

Full dictionary entry for "mau" with definition, IPA, and generated misspellings. Word entry
Full dictionary entry for "mer" - compare definitions side by side with the headword page. Word entry
This pair ranks #45,684 of 75,631 scored Portuguese confusable pairs in this corpus vintage. Corpus statistics
"mau" and "mer" also get mixed up with nearby pairs, the highest-scored neighbour is "maa vs mer". Nearby pair

Confusion rank #45,684 of 75,631 scored Portuguese pairs, corpus vintage 2026-09-03, not spelling advice.