The meanings of adjectives can be altered by adding a prefix. Most people know that mal- makes opposites, but the meaning of ne- is a bit more vague. How should I know when to use ne- instead of mal-?

Some of them I just know by experience. The only ne-word I can think of right now is nekredebla. Examples with mal- are malsana, malforta and malgaja.

Here are some of the adjectives I am wondering about:

necesa, utila, interesa, grava, certa, klara, kontenta, kapabla, simila, sama

  • Can nevera describe things that aren't coherent enough to be true or false? Commented Jul 31, 2017 at 5:19

5 Answers 5


To your list of prefixes, you could add sen-.

If something has a clear opposite, then it's mal- (e.g. malvera, malsimila, malsama).

If it's something that is either there or not, then it's -ne (e.g. nenecesa).

If the quality is lacking, then it's sen- (e.g. senutila).

Most of the words you listed can go more than one way. For example:

  • neinteresa
  • seninteresa
  • malinteresa

Of the three, malinteresa is the least interesting.

  • 1
    You mean ne-, not -ne, I guess.
    – Pierre
    Commented May 30, 2018 at 11:21
  • Correct. It should be ne- -- a prefix. Commented Jul 17, 2018 at 15:32

The meaning of ne is not really vague: It is just negation. You can use either to express what you mean, but in some cases the opposite and negation coincide: For instance with vera; nevera and malvera are the same, because anything that is ‘not true’ is ‘false’. In these cases I think mal might be preferred. (In this case I found only 2 instances of \bnever[aeiou](s)?\b and 90 of \bmalver[aeiou](s)?\b in tekstaro.)

Malnecesa is something like ‘superfluous’, while nenecesa is just ‘not necessary’, which need not be superfluous, but just not required.
Further examples, malutila would be something like ‘detrimental’, while neutila is just ‘useless’. Neklara is unclear, while malklara is vague. Again, nesama and malsama coincide, because the opposite of ‘being the same’ is ‘being different’, which is ‘not being the same’.


Some words don't have opposites. People often think of invisible (nevidebla) as the opposite of visible (videbla) but it isn't. It's either see-able or it's not.


There is no a general rule, but you can get it by logic.

  • Sometimes, mal- and ne- may be used to achive the same meaning, e.g.:

    mal/kontenta, ne/kontenta: Deziranta ion alian ol tion, kion oni havas (PIV)

  • Other times, the difference could be a subtle nuance:

    ne/certa: Duba (PIV)
    mal/certa: Tute ne certa (PIV)

    ne/klara: Konfuza, nedistingebla (PIV)
    mal/klara: Ne tute klara (PIV)

  • Other times, the meaning may be remarkably different:

    ne/utila: (= sen/utila) Tia, ke ĝi donas nenian utilon (PIV)
    mal/utila: Tia, ke ĝia uzo, efiko, rezulto alportas aŭ povas alporti malbonon, difekton, malprofiton (PIV)

Pomego has a paragraph about the difference between mal and ne.


Ne = no or not

Mal = opposite


  • White = blanka - The house is white
  • Not white = neblanka - The house is not white
  • Black = malblanka - The house is black


  • Useful = utila
  • Not useful = neutila
  • A hindrance (the opposite of useful) = malutila


In English, we can say "He is unhealthy" or "He is sick". Both have different meanings although they are similar. There are many cases where it doesn't make sense to use Mal- because there is no opposite. For example, I can't say Malauxto, but I can say Malforta.

  • 4
    "malblanka" does not mean "black". Colors do not have "logical opposites".
    – Lee
    Commented Dec 29, 2016 at 13:06
  • 1
    @Lee being a logical language and since a color wheel exists, couldn't it work out given mal[color] isn't a word that means something else?
    – nelomad
    Commented Nov 7, 2017 at 23:02

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