This joint let's you go, if you get it? (3,5)
I believe the answer is:
the elbow
'this joint let's you go if you get it?' is the definition.
The definition and answer can be both man-made objects as well as being singular nouns.
Perhaps they are linked in a way I don't understand?
'joint let's you go if you get it?' is the wordplay.
I cannot really understand how this works, but
'joint' could be 'elbow' (joint of the body) and 'elbow' is found within the answer.
'it?' could be 't' (abbreviation. e.g. in 'tis) and 't' is located in the answer.
The remaining letters 'he' is a valid word which might be clued in a way I don't understand.
This explanation may well be incorrect...
Can you help me to learn more?