Actually danny may have touched on something there- maybe the wordplay is that "bluntest2 sounds like "bland test"- at leats it does if I put on my dreadful Irish accent which I often use when trying to solve RTE clues
>"Hmm, FF... but where would 'the most tactless' fit in with Blandest?"
It wouldn't. The answer is bluntest, the definition being tactless. It sounds like "bland test " (straightforwrd exam) if 'bland test' is said in an Irish accent type of way- in my head at least.