Same goes with “for”, which you sometimes hear in readbacks like “leaving 4000 for 3000”. It should be something unambiguous like “4000 descending 3000” instead.
Quoth Wikipedia: The word "takeoff" is now spoken only when the actual takeoff clearance is given, or when cancelling that same clearance (i.e. "cleared for takeoff" or "cancel takeoff clearance"). Up until that point, aircrew and controllers should use the word "departure" in its place (e.g. "ready for departure").