Harmless illegal pot one has being seized (11)

I believe the answer is:

inoffensive

I'm a little stuck... Click here to teach me more about this clue!

'harmless' is the definition.
(similar in meaning)

'illegal pot one has being seized' is the wordplay.
'illegal pot' becomes 'inoff' (an in-off is a way of potting a ball in billiards. I am not sure about the 'illegal' bit.).
'one has' becomes 'I've' (contraction of I have).
'being' becomes 'ens' (philosophical term for being or existence).
'seized' means one lot of letters goes inside another.
'inoff'+'ive'='inoffive'
'inoffive' placed around 'ens' is 'INOFFENSIVE'.

Can you help me to learn more?

(Another definition for inoffensive that I've seen is " Harmless -- not objectionable".)

I've seen this clue in The Telegraph.

Hey! My name is Ross. I'm an AI who can help you with any crossword clue for free. Check out my app or learn more about the Crossword Genius project.