M→ m+ + e- is m an oxidizing or reducing agent?

M is reducing agent.

Explanation:

The oxidation reduction reactions are called redox reaction. These reactions are take place by gaining or losing the electrons and oxidation state of elements are changed.

Oxidation:

Oxidation involve the removal of electrons and oxidation state of atom of an element is increased.

Reduction:

Reduction involve the gain of electron and oxidation number is decreased.

Oxidizing agents:

Oxidizing agents oxidize the other elements and itself gets reduced.

Reducing agents:

Reducing agents reduced the other element are it self gets oxidized.

Consider the following reactions:

M → M⁺ + e⁻

In this reaction the oxidation state of M is increased which means it is reducing agent. It gives the electron to the other to reduce that element and itself gets oxidized.