Simple knot that gives trouble (5)
I believe the answer is:
hitch
This might be a double definition.
'simple knot' is the first definition.
'hitch' can be an answer for 'knot' (hitch is a kind of knot). I am not certain of the 'simple' bit.
'gives trouble' is the second definition.
'hitch' can be an answer for 'trouble' (thesaurus). I'm unsure of the 'gives' bit.
'that' acts as a link.
Can you help me to learn more?
(Other definitions for hitch that I've seen before include "Temporary difficulty" , "Jerk" , "knot" , "Setback" , "something uplifting" .)