Excuse used before arrival of phone messaging (7)

I believe the answer is:

pretext

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

'excuse' is the definition.
(a pretext is an excuse or pretence)

I don't understand how the remainder of the clue works.

Can you help me to learn more?

(Other definitions for pretext that I've seen before include "Excuse for an action" , "Reason put forward to conceal the true one" , "Stalking-horse" , "Fictitious reason in order to conceal the real one" , "Justification, excuse" .)

I've seen this clue in The Sun.

Want a hint initially instead of a full solution? Install my app