When is the prefix ne- and when is it mal-?

Question

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

Answer 1

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.

Answer 2

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’.

Answer 3

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.

Answer 4

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.

Answer 5

Ne = no or not

Mal = opposite

Blanka:

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

Utila:

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

Note:

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.