Implicit intents are the ones that can be understood by the context of what is being said. For example, if someone says “I want to go to the store”, it is implied that they want to purchase something.
Explicit intents are more specific and are stated explicitly. For example, if someone says “I want to go to the store and buy some milk”, it is explicit that they want milk.
Implicit intents are usually easier for humans to interpret because they use natural language processing (NLP) which is based on patterns in human speech. Explicit intents require a machine learning process which involves more programming logic and data mining algorithms.