Could you tell me how to understand the word "to patronise"

To patronise someone is to "talk down" to them. Treat them like a child and as though they don't understand what is going on around them. It usually is meant in a more malicious way than just explaining something to someone

'to patronise' someone means to pitty them and treat them like a younger person and to not respect there views on things. it's hard to explain really : D