矮躯[waiku] small stature
矮鶏[chabo] (Japanese) bantam
矮小[waishou] diminutive
矮人[waijin] dwarf
矮星[waisei] dwarf star

矮樹[waiju] low or short tree
矮惑星[waiwakusei] dwarf planet (e.g. Pluto)
白色矮星[hakushokuwaisei] white dwarf (star)
赤色矮星[sekishokuwaisei] red dwarf (star)
褐色矮星[kasshokuwaisei] brown dwarf (star)