From 《三国志·魏志·董昭传》: 秘而不露，使权得志，非计之上 - "to keep it secret and not reveal it, letting Sun Quan get his way, is not a first-rate plan". A piece of strategic advice during the Three Kingdoms.
grammar
Apostrophe: mì'ér-bùxuān. The syllable break comes before the vowel-initial 而 (ér).
