service has 14 distinct synonyms spread across 11 of its 18 senses. Each sense below keeps its own list, because a synonym belongs to a meaning and not to a word: swapping one sense's substitute into another sense's sentence is how a thesaurus makes writing worse. Its one recorded opposite is disservice.
Counts are distinct word forms across every sense. A synonym that appears under three senses is counted once here and shown three times below, under each sense it belongs to.
work done by one person or group that benefits another
“budget separately for goods and services”
an act of help or assistance
“he did them a service”
the act of public worship following prescribed rules
“the Sunday service”
employment in or work for another
“he retired after 30 years of service”
a force that is a branch of the armed forces
Canadian writer (born in England) who wrote about life in the Yukon Territory (1874-1958)
tableware consisting of a complete set of articles (silver or dishware) for use at table
(law) the acts performed by an English feudal tenant for the benefit of his lord which formed the consideration for the property granted to him
(sports) a stroke that puts the ball in play
“his powerful serves won the game”
the act of delivering a writ or summons upon someone
“he accepted service of the subpoena”
periodic maintenance on a car or machine
“it was time for an overhaul on the tractor”
the performance of duties by a waiter or servant
“that restaurant has excellent service”
Synonyms, antonyms and the broader and narrower relations for service come from Princeton University’s WordNet. Full sources and licences.