on the sly (adverb) covertly: clandestine, underhandedly
Sinonime: banal,
blah*,
boring, dull, dull as dishwater, flat, flavorless, ho hum,
humdrum,
insipid, milk-and-water,
monotonous, nerdy,
nothing, pabulum, sapless,
tame,
tedious, unexciting, uninspiring, uninteresting, unstimulating, vanilla, vapid, waterish,
watery,
weak, wimpy, wishy-washy,
zero*
Antonime: delicious,
distinctive,
sharp,
tasty,
yummy