Very unpleasant 144? (5)
I believe the answer is:
gross
'144?' is the definition.
(gross can mean the number 144)
I don't understand the rest of the clue.
Can you help me to learn more?
(Other definitions for gross that I've seen before include "With no deductions; coarse" , "Foul" , "Twelve dozen" , "Unattractively large; vulgar" , "Excessively - large number" .)