'deep-rooted' originates from the combination of 'deep' and 'rooted', where 'deep' refers to a significant depth and 'rooted' refers to being firmly established.

'deep-rooted' evolved from the Old English word 'deop' meaning 'deep' and 'roted' from 'root', eventually forming the modern English word 'deep-rooted'.

Initially, it meant 'having roots that go deep into the ground', but over time it evolved into its current meaning of 'firmly established and difficult to change'.