tie has 21 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 untie.
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.
neckwear consisting of a long narrow piece of material worn (mostly by men) under a collar and tied in knot at the front
“he stood in front of the mirror tightening his necktie”
a social or business relationship
“a valuable financial affiliation”
(music) a slur over two notes of the same pitch; indicates that the note is to be sustained for their combined time value
one of the cross braces that support the rails on a railway track
“the British call a railroad tie a sleeper”
a cord (or string or ribbon or wire etc.) with which something is tied
“he needed a tie for the packages”
Synonyms, antonyms and the broader and narrower relations for tie come from Princeton University’s WordNet. Full sources and licences.
limit or restrict to
“I am tied to UNIX”
connect, fasten, or put together two or more pieces
“Can you connect the two loudspeakers?”
make by tying pieces together
“The fishermen tied their flies”