unimposing (adj.)youdaoicibaDictYouDict
"unimpressive," 1809, from un- (1) "not" + imposing.
unimpressed (adj.)youdaoicibaDictYouDict
1861, "not awed," from un- (1) "not" + past participle of impress (v.). Used earlier in a sense of "not subjected to restraint" (1743). Unimpressive is recorded from 1796.
dorpyoudaoicibaDictYouDict
"A small rural town or village (often used to suggest that a place is backward or unimpressive)", Dutch, 'village' (see thorp).