From Arabic مِسْكِين (miskīn).
1) poor (with no possessions or money)
hafifu (note: also means weak)
مِسْكِين • (miskīn) (feminine مِسْكِينَة (miskīna), masculine plural مَسَاكِين (masākīn))
1) poor (unfortunate)
In English " poor teacher" can also mean that he/she is not a good teacher rather than an "underpaid teacher". "Hafifu", according to my online dictionary, is not an antonym of maskini, but means," trifling , mediocre, frivolous or poor in quality."