1.
cheap; inexpensive
Low in price. A somewhat old-fashioned usage.
安直な値段で買えた。
I was able to buy it at a cheap price.
もう少し安直な店はないかな。
I wonder if there's a cheaper shop.
昔はこの辺りは物価が安直だった。
Prices used to be cheap around here in the old days.
2.
easy; simplistic; superficial
Taking the easy way without much thought or effort. Often carries a critical nuance of being too simple-minded or lazy in approach.
安直な考えは危険だ。
Simplistic thinking is dangerous.
安直に結論を出すべきではない。
You shouldn't jump to a conclusion too easily.
安直な方法に頼ると、あとで後悔することになる。
If you rely on an easy approach, you'll end up regretting it later.
Sense 1 (cheap/inexpensive) is somewhat dated and rarely used in modern conversation. Sense 2 (easy/simplistic) is the more common modern usage and almost always carries a negative nuance — it criticizes a lack of serious thought or effort. Common collocations: 安直な考え (simplistic thinking), 安直に考える (to think too simply), 安直な方法 (an easy/lazy method).