na-adjective
Describes a person or manner that is straightforward and honest, without hiding thoughts or feelings. Often used for personality or communication style.
彼はとてもフランクな人で、誰とでもすぐに打ち解ける。
He is a very frank person and quickly gets along with anyone.
フランクに意見を言ってくれてありがとう。
Thank you for giving your opinion so candidly.