### Clue: Form one question in English exam, dropping second half of another (9)
### Answer: ETIQUETTE 
 ### Explanation: Definition: Form 
 [ I(Roman numeral for "one") + QU(abbrev. for "question") ] **contained in**(in) [ E(abbrev. for "English") + "test"(an exam) **minus**(dropping) "s"(abbrev. for "second" in time notation) ] + **the 1st 2 letters of**(half of) "test"(another exam).
Defn: The set of conventional and correct behaviour in polite society.