bland

lacking taste or flavor or tang; "a bland diet"; "insipid hospital food"; "flavorless supermarket tomatoes"; "vapid beer"; "vapid tea"

lacking stimulating characteristics; uninteresting; "a bland little drama"; "a flat joke"

smoothly agreeable and courteous with a degree of sophistication; "he was too politic to quarrel with so important a personage"; "the manager pacified the customer with a smooth apology for the error"