What is the meaning of Chandee?

Chandee is Durga Devi.

Durga Saptashati or Devi Mahatmya is called Chandee Path.

Chandee or Chandika.

Chandika Parameshwari.

The name Chandee is derived from the root चडि कोपे in Sanskrit.

A blazing Sun is called चण्डभानुः.

A fierce storm is called चण्डमारुतः.

Chandee means anger, rage embodied.

The fierce, angry form of Devi is called Chandee or Chandika.

Rudra is anger embodied in the male form.

नमस्ते रुद्र मन्यव उतो त इषवे नमः

The term manyu here means anger,

Namaskaras to your anger, Oh Rudra, this is how Sri Rudram begins.

The purpose of manifestations of Devi in Durga Saptashati is to protect the Devas.

In all the situations, the Devas have been overpowered by the Asuras.

The Asuras can be destroyed only through waging war.

In the second manifestation, this is clearly depicted.

Mahishasura has thrown out all the Devas from Swarga.

They go to the Trimurthys seeking restoration of order.

Devas are agitated and infuriated.

The anger of the Trimurthys and the Devas comes out from their bodies and becomes a huge mountain of fire.

From this Devi manifests.

She is anger personified.

She is Parameshwari.

The supreme ruler.

A ruler can be good only if the subjects have a fear of punishments and the severity of punishments.

That is how a good ruler maintains law and order.

भीषास्माद्वातः पवते भीषादेति सूर्यः।

भीषास्मादग्निश्चेन्द्रश्च मृत्युर्धावति पञ्चमः॥

It is in fear of this supreme ruler that the wind blows, Sun rises, fire gives heat, and Indra rules properly.

Why? 

Even death is scared of her.

That is because of her anger.

That is because she is Chandee.