used in expressions that convey frustration and futility, such as 無奈|无奈[wu2 nai4] and 莫可奈何|莫可奈何[mo4 ke3 nai4 he2] (literary) / used for its phonetic value in writing foreign words
奈
=
大
+
示
:
Napoleon (n) wants to put his guideon (示) on the peak of Mount Sinai (奈) in the airplane's bathroom (ai4), but the robot (大) normally responsible for carrying his guideon is broken. Without any better option (奈) Napoleon will have to carry up the guideon himself.