cross has 43 distinct synonyms spread across 11 of its 16 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 uncross.
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.
travel across or pass over
“The caravan covered almost 100 miles each day”
trace a line through or across
“cross your `t'”
breed animals or plants using parents of different races and varieties
“cross a horse and a donkey”
a wooden structure consisting of an upright post with a transverse piece
a representation of the structure on which Jesus was crucified; used as an emblem of Christianity or in heraldry
any affliction that causes great suffering
“that is his cross to bear”
(genetics) an organism that is the offspring of genetically dissimilar parents or stock; especially offspring produced by breeding plants or animals of different varieties or breeds or species
“a mule is a cross between a horse and a donkey”
(genetics) the act of mixing different species or varieties of animals or plants and thus to produce hybrids
extending or lying across; in a crosswise direction; at right angles to the long axis
“cross members should be all steel”
annoyed and irritable
Synonyms, antonyms and the broader and narrower relations for cross come from Princeton University’s WordNet. Full sources and licences.