connect has 13 distinct synonyms spread across 5 of its 11 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 disconnect.
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.
connect, fasten, or put together two or more pieces
“Can you connect the two loudspeakers?”
join by means of communication equipment
“The telephone company finally put in lines to connect the towns in this area”
land on or hit solidly
“The brick connected on her head, knocking her out”
join for the purpose of communication
“Operator, could you connect me to the Raffles in Singapore?”
be scheduled so as to provide continuing service, as in transportation
“The local train does not connect with the Amtrak train”
establish a rapport or relationship
“The President of this university really connects with the faculty”
establish communication with someone
“did you finally connect with your long-lost cousin?”
hit or play a ball successfully
“The batter connected for a home run”
Synonyms, antonyms and the broader and narrower relations for connect come from Princeton University’s WordNet. Full sources and licences.