Clue: Common sense shown by doctor with refusal to entertain books lacking in variety and interest (10)
Answer: MONOTONOUS
Explanation: Common sense shown by doctor with refusal to entertain books lacking in variety and interest (10)
**MO** (Medical Officer, so "doctor") + **NO** (refusal) "entertaining" **O.T. **(Old Testament, so "books") + **NOUS** (common sense)