This is the 791st most frequent Persian word.
مستقیم
Direct.
Here, "مستقیم" is used as an adjective meaning "straight" to describe the road's direction.
این جاده مستقیم به شهر میرود.
This road goes straight to the city.
In this sentence, "مستقیم" is an adjective meaning "direct" to describe the type of phone line.
آیا این خط تلفن مستقیم است؟
Is this phone line direct?
Here, "مستقیم" is used as an adverb meaning "directly" to indicate the mode of communication.