Antonyms of verb differ

1 of 2 senses of differ

Sense 1
differ -- (be different; "These two tests differ in only one respect")
       Antonym of equal (Sense 1)
      => equal, be -- (be identical or equivalent to; "One dollar equals 1,000 rubles these days!")

Synonyms/Hypernyms (Ordered by Estimated Frequency) of verb differ

2 senses of differ

Sense 1
differ -- (be different; "These two tests differ in only one respect")

Sense 2
disagree, differ, dissent, take issue -- (be of different opinions; "I beg to differ!"; "She disagrees with her husband on many questions")