150 may riot over European money for weapon (8)
I believe the answer is:
claymore
'for weapon' is the definition.
(type of medieval sword)
'150 may riot over european money' is the wordplay.
'o50' becomes 'CL' (Roman numerals).
'riot' indicates an anagram.
'over' means one lot of letters goes inside another.
'european money' becomes 'ore' (I have seen 'foreign money' mean 'ore' so perhaps 'money' could also mean 'ore'. I am not sure about the 'european' bit.).
'may' is an anagram of 'aym'.
'cl' going within 'aym' is 'claym'.
'claym'+'ore'='CLAYMORE'
Can you help me to learn more?
(Other definitions for claymore that I've seen before include "pipe" , "Something that can cut" , "Scottish Highlanders' broadsword" , "Scottish highlander's sword" , "Two-edged broadsword" .)