A colourful though unoriginal thing to do (5)

'unoriginal thing to do' is the definition.
I don't know anything about this answer so I cannot tell whether it can be defined by this definition.

'a colourful' is the wordplay.
I cannot quite understand how this works, but
'colourful' could be 'red' (similar in meaning) and 'red' is located in the answer.
The remaining letters 'ye' is a valid word which might be clued in a way I don't see.
This may be the basis of the clue (or it may be nonsense).

'though' acts as a link.

Can you help me to learn more?