Definition
Used to indicate that someone or something is slightly different from a particular description.
不完全是；不完全符合
He's not exactly handsome, but he has a certain charm.
他並不算是帥，但他有某種魅力。
It's not exactly the best picture of them, but it's the best of the lot.
這並不是他們最好看的照片，但在這批照片中算是最好的了。
She wasn't exactly typecast as an aging socialite, but it came close.
她並沒有完全被定型為一個老去的社交名媛，但也差不多了。
Used to indicate that something is not completely true.
不完全是
"So you gave her your iPod?" "Not exactly, I just lent it to her."
「所以你給了她你的iPod？」「不完全是，我只是借給她。」
"So the British won the war?" "Well, not exactly."
「所以英國人贏了這場戰爭？」「嗯，不完全是。」
"You were planning on leaving the area." "Not exactly. I planned on coming back eventually."
「你原本打算離開這個地區。」「不完全是。我計劃最終會回來。」
Used to indicate that something is the opposite of a particular description.
不完全是；井非
Answer the question - it's not exactly difficult.
回答這個問題——這並不難。
Journalists aren't exactly known for their compassion.
記者們並不以他們的同情心著稱。
Smoked salmon and fresh figs aren't exactly the kind of things we eat most days.
煙燻鮭魚和新鮮無花果並不是我們大多數日子會吃的東西。