From Longman Dictionary of Contemporary Englishplumplum1 /plʌm/ ●●○ noun 1 
[countable]DFFHBP a small round juicy fruit which is dark red, purple, or yellow and has a single hard seed, or the tree that produces this fruit juicy ripe plums2 [uncountable]CC a dark purple-red colour3 [countable] informal something very good that other people wish they had, such as a good job or a part in a play The first job I had was a real plum. → plum pudding
[countable]DFFHBP a small round juicy fruit which is dark red, purple, or yellow and has a single hard seed, or the tree that produces this fruit juicy ripe plums2 [uncountable]CC a dark purple-red colour3 [countable] informal something very good that other people wish they had, such as a good job or a part in a play The first job I had was a real plum. → plum puddingExamples from the Corpus
plum• The contract is a plum for Browning and Co.• Rosy pinks, rich coppers and deep plums are the big fashion news.• Either plums or blackberries, not both.• If plums are difficult to find or not.• All varieties of plum, apple, and pear trees, grew in unison.• She walked across the scuffed floors toward the cupboard and pulled out several packages of tamarind candy and salted plums.• An image that captures the dichotomy of possibilities in getting older is the plum versus the prune.• He said that wild plums were delicious.plumplum2 adjective 1 → plum job/role/assignment etc2 CChaving a dark purple-red colourExamples from the Corpus
plum• For me, it was a plum assignment.• And he will be rewarded with a plum chairmanship, probably the Environment and Public Works Committee.• Neither Zeckendorf nor Soderberg dared to believe that such a plum deal would come to them, but they started discussions anyway.• The good news was he had landed a plum job on the mortgage trading desk.Origin plum1 Old English plume, from Latin prunum; → PRUNE2 