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Hint 1Meaning
flightless birds having flat breastbones lacking a keel for attachment of flight muscles: ostriches; cassowaries; emus; moas; rheas; kiwis; elephant birds
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Hint 2Best answers
Possible answers to the crossword clue FLIGHTLESS BIRD include RHEA (4 letters), KIWI (4 letters), WEKA (4 letters). Compare these suggestions with the number of squares and any crossing letters in your puzzle.