unimpressive

adjectives

not capable of impressing
unimpressive
antonym
impressive
is similar to
lacking in impressiveness
"on the whole the results of this system are unimposing"
unimposing
see also
marked by meekness or modesty; not arrogant or prideful
"a humble apology"; "essentially humble...and self-effacing, he achieved the highest formal honors and distinctions"- B.K.Malinowski
humble