Round tubes, bent out of shape and slow on the uptake (6)
I believe the answer is:
obtuse
'slow on the uptake' is the definition.
(I've seen this in another clue)
'round tubes bent out of' is the wordplay.
'round' becomes 'o' (o is a circular letter).
'bent' is an anagram indicator.
'out of' is an insertion indicator (some letters on the outside of others).
'tubes' is an anagram of 'btuse'.
'o' inserted inside 'btuse' is 'OBTUSE'.
'shape and' acts as a link.
I am not very happy about this link. Some or all of it may be part of another bit of the clue.
Can you help me to learn more?
(Other definitions for obtuse that I've seen before include "Can't quite see the angle" , "Angles could be" , "(Of angle) between 90° and 180° - dull" , "Dull, non-perceptive" , "Mentally slow - kind of angle" .)