出其不意

to do sth when least expected (idiom); to catch sb off guard

to go out / to come out / to occur / to produce / to go beyond / to rise / to put forth / to happen / (used after a verb to indicate an outward direction or a positive result) / classifier for dramas, plays, operas etc

variant of 出[chu1] (classifier for plays or chapters of classical novels)

his / her / its / their / that / such / it (refers to sth preceding it)

no; not so / (bound form) not; un-

unexpectedly / unawareness / unpreparedness

Italy / Italian / abbr. for 意大利[Yi4 da4 li4]

idea / meaning / thought / to think / wish / desire / intention / to expect / to anticipate

Italy; Italian (abbr. for 意大利[Yi4 da4 li4])

to catch an enemy off guard with a surprise attack (idiom, from Sunzi's "The Art of War" 孫子兵法|孙子兵法[Sun1 zi3 Bing1 fa3])