What does "amateurishness" mean?

The quality of being amateurish.

Amateurishness

Common synonyms include: greenness, ignorance, immaturity, inartistry, inexperience, unfamiliarity.

noun

noun ·Rare ·Advanced level

Noun

1
The quality of being amateurish. uncountable
"He betrays his amateurishness in a hundred ways."
2
something that demonstrates a lack of professional competency wordnet

"He betrays his amateurishness in a hundred ways."

From amateurish + -ness.