Immature, Inexperienced, Not Yet Good At
noun, な adjective, の adjective
Something that has not yet ripened, is, well, unripe. This is often used figuratively to say that someone is either immature or inexperienced, so you'll often encounter those usages!
This is a jukugo word that uses the on'yomi readings of the kanji. You should be able to read this on your own.
I'm still not that good at it and there are many things I don't understand, but I'll do my best.
Despite my inexperience, I provided an explanation.
I keenly felt my own immaturity.
I used to be immature and I did whatever I wanted too.