Be burdensome in the way suggested (5)
I believe the answer is:
weigh
'be burdensome' is the definition.
(I've seen this before)
I cannot understand how the remainder of the clue works.
Can you help me to learn more?
(Other definitions for weigh that I've seen before include "Evaluate (in mind)" , "Measure the mass of something using scales" , "Ponder" , "Estimate the value of" , "Consider carefully" .)