### Clue: Shrewd like teacher taking English for men (6)
### Answer: ASTUTE 
 ### Explanation: Definition: Shrewd
 AS(like/similar to, as expressed in similes) + "tutor"(a teacher) ***with** *E(abbrev. for English) ***replacing***(taking … for) "or"(abbrev. for "other ranks", non-commissioned men in the military).