sub ‧ stan ‧ dard /ˌsʌbˈstændəd◂ $ -ərd◂/ BrE AmE adjective
[ Word Family: noun : ↑ standard , ↑ standardization ; adjective : stardard, ↑ substandard ; verb : ↑ standardize ]
not as good as the average, and not acceptable ⇨ non-standard , standard :
substandard housing