Is joking about the safety device (8)
I believe the answer is:
banister
'safety device' is the definition.
The answer and definition can be both man-made objects as well as being singular nouns.
Maybe there's a link between them I don't understand?
'is joking about' is the wordplay.
'joking' becomes 'banter' (I've seen this before).
'about' is an insertion indicator.
'is' going within 'banter' is 'BANISTER'.
'the' is the link.
Can you help me to learn more?
(Other definitions for banister that I've seen before include "Upright supporting handrail of stairs" , "Stair-rail" , "Stair handrail and supports" , "Staircase railing" , "support at hand on flight" .)