This cheese smells slightly off. Here 'off' is

• This cheese smells slightly off.
- Here 'off' is - Adjective.

In the sentence "This cheese smells slightly off.," the word "off" functions as an adjective. It describes the state or condition of the cheese, meaning that it is no longer good or fresh.

• Off: [Adjective]
English meaning: (of food) no longer fresh enough to eat or drink.
Bangla meaning: (খাদ্য) আর খাওয়ার বা পান করার জন্য যথেষ্ট ভালো নয়।

Example:
- The fruit looks slightly off.
- That sandwich feels slightly off.
- The sauce seems slightly off.

Source: Oxford Dictionary.