Definition of grouses:
(v) :
(intransitive, originally military slang, informal) To complain or grumble.
(n) :
(informal) A cause for complaint; a grumble.
(n) :
(countable) Any of various game birds of the subfamily Tetraoninae which inhabit temperate and subarctic regions of the Northern Hemisphere; specifically, the red grouse (Lagopus lagopus scotica) native to heather moorland on the British Isles.
(n) :
(uncountable) The flesh or meat of this bird eaten as food.
(v) :
(intransitive) To hunt or shoot grouse.
(adj) :
(Australia, New Zealand, slang) Excellent.