Qualitative and relative adjectives
Adjectives that name an attribute directly and can be graded are qualitative: go‘zal (beautiful), shirin (sweet), oq, aqlli. They accept -roq: go‘zalroq (more beautiful), shirinroq. Adjectives that express an attribute by relation to another concept and show no degree are relational: qishki (winter), ko‘chma (portable), devoriy (wall), ilmiy (scientific). They do not accept -roq: we do not say “qishkiroq”. Relational adjectives are often formed with -gi, -ma, -iy. Trying -roq is a handy way to tell the two groups apart.
“The -roq test”: add -roq to the adjectives; if it works write qualitative, if not relational.