It's not like deci-meter. The root of decimal is decim. Adding -al to it makes it an adjective.
9.0
De-ci-mal
Mal means bad, or badly.
Mal voisin means bad neighbour
Darth maul mal is Spanish for bad, as in "not good." The opposite of good.
"mal-aimée" (masculine: mal-aimé) means "badly-loved" in French.
mal
"Mal Vriende" Literally means "Crazy Friends" "Mal" means crazy but can also be slang for Cool
Pas mal means 'not bad' in French.
Mal means times, as in "three times a day" or "two times two is four" It can also mean Meal, but then it would be with a capital "M". It is sometimes part of a phrase like "warte mal" - "wait a bit" or "schau mal!" - "just look!"
Spelt 'Que mal' in Spanish, it menas How awful! or That's awful!
j'ai mal à l'épaule - my shoulder hurts/is hurting me