Please teach me!

[strato8021]

Hi teacher! I'm a korean and English Beginner. I think this site is very useful for student studying english.

I have a question!

In this site, I take a test at [Adjectives ending -ful & -less].

The question is "We can say worthless but not worthful" and correct answer is TRUE

I don't know why 'worthful' is incorrect.

I want to know difference '-less' & '-ful'

Thank you for your big help.

[Soup]

-ful means abundant, full of.
-less means lack of.

Full of worth is the opposite of worthless (lack of value).

[saman mirza]

-ful and -less are suffices, they are used at the end of words to change the meaning. But they cannot be used with every word, and they do not always form similar meanings.
for example, there is no such word as worthful. the opposite of worthless would be valuable. See, a completely different word. But, another word for worthless is valueless!