We don't have synonyms for murren yet — it may be a rare, specialized, newly coined, or misspelled word. The closest thesaurus entries we have are murrey, curren and murrin.
(n) :
Obsolete form of murrain. [(archaic, uncountable) Infectious disease; pestilence, plague; (countable) sometimes used in curses such as a murrain on someone: an outbreak of such a disease; a plague.]
(n) :
Obsolete form of murrain. [(archaic, uncountable) Infectious disease; pestilence, plague; (countable) sometimes used in curses such as a murrain on someone: an outbreak of such a disease; a plague.]