にちようび
Sunday
nichiyoubi
JMdict 1464900
にちようびは日曜日はSundayやすみ休みday off
は (topic) raises 日曜日にちようび (Sunday) as the topic — "as for Sunday…". Then comes 休みやすみ (day off), with no copula at all. Dropping です (is) makes it a short, casual note rather than a formal statement.
hanamaru