Honest
Upfront, Obedient
な adjective
Remember how 直 can also mean "direct?" Well, if someone has an element of directness to them, they're probably a really honest and upfront person.
素直 usually describes someone who's sincere, emotionally open, willing to listen, and not stubborn. In some contexts, it can also imply someone is obedient or compliant. For example, a child who always does what they're told without objection might be called 素直.
The reading for this is a bit of a weird one. It uses on'yomi for 素, then it uses the kun'yomi for 直. You know both readings, but it's all a little strange, so here's a mnemonic help you:
If you're honest and upfront with yourself, you know it's time to sue now(すなお). What that person did to you… they definitely deserve be sued, now. Don't try to brush it off, don't let them silence you. Be obedient to your feelings and sue now!
素直に認めろよ。
Just be honest and admit it.
君の素直な気持ちが聞けてうれしいよ。
I'm glad I could hear your honest feelings.
人のアドバイスを素直に受け入れられる素直さって大事だよね。
It's important to have the openness to accept advice from others.