The opposite of 弯 (wān curved or bent) is 直 (zhí), which means straight, directly, straightforward, upright or just.
直接 (zhíjiē) means direct, directly or immediately.
Nǐ kěyǐ zhíjiē hé tā liánluò.
You can contact him directly.
直达 (zhídá) means nonstop. Therefore, 直达车 (zhídá chē) is a bus that will go directly to the destination without making stops on the way.
We have previously (4/9/14) learned that 半径 (bànjìng) is the radius of a circular shape. The diameter is called 直径 (zhíjìng).
直流电 (zhíliúdiàn) is direct current. Alternating current is called 交流电 (jiāoliúdiàn).
直肠 (zhícháng) is the straight section of the large intestine, or rectum. On the other hand, 直肠子 (zhíchángzi) refers to a person who is straightforward and outspoken, or 直爽 (zhíshuǎng).
Tā gèxìng zhíshuǎng.
He is straightforward in personality.
You could also describe such a person by using a four-character Chinese idiom:
He is frank and outspoken.
直截了当 (zhíjiéliǎodàng) means straightforward, blunt or pointblank.
Tā zhíjiéliǎodàng shuō tā bù ài tā.
He said pointblank that he did not love her.
As “he” and “she” sound exactly the same in Chinese, it will not be possible to tell whether a man is dumping a woman or a woman is dumping a man if you are not familiar with the situation and just heard someone utter the above sentence.
一直 (yīzhí) means continuously, always or all along.
Tā yīzhí bùtíng de kū.
She kept crying non-stop.
直到 (zhídào) means up until.
Wǒ yǒngyuǎn ài nǐ, zhídào hǎikūshílàn
I will love you forever, until the seas run dry and the rocks are totally eroded.
直觉 (zhíjué) is one’s intuition or gut feeling.
Wǒ de zhíjué shì tā méiyǒu chéngyì.
My gut feeling is that he is not sincere.
正直 (zhèngzhí) means honest, upright and fair.
理直气壮 (lǐzhíqìzhuàng) means acting bold and assured because one has justice on one’s side.
间接 (jiànjiē) means indirect or indirectly.
间隔 (jiàngé) is the interval between two events or the space separating two objects.
房间 (fángjiān) are rooms that are separated from each other by walls.
间断 (jiànduàn) means interrupted or disconnected.
Wǒ hé tā tōngxìn duōnián, méiyǒu jiànduàn.
I corresponded with him for years without interruption.
中间 (zhōngjiān) means in the middle or being between two things or persons. Therefore, a middleman is called 中间人 (zhōngjiānrén), and a spy is called 间谍 (jiàndié).
“Directly” and “directly” are adverbs. You might want to review Chapter 17 of “Learn Chinese through Songs and Rhymes” for the correct placement of an adverb in a sentence.