Simple Definition:

Sentiment refers to the emotions or opinions expressed by a person towards a particular topic, person, or event. It can be positive, negative, or neutral. Sentiment is often determined by analyzing the language used or the tone of a person’s communication. For example, if someone says "I love this movie", their sentiment towards the movie is positive, while if they say "I hate this movie", their sentiment is negative.

Very Simple Definition:

Sentiment means how someone feels about something. It can be either good, bad, or neither. For example, if someone says they love a movie, that’s a good sentiment. If they say they hate it, that’s a bad sentiment.