What is the meaning of -ül?

Form of -il after the vowels Ö / Ü and a consonant other than L.

Added to an adjective to form a middle-voice verb. It is similar to -edik.

as, with the intention of (front-vowel variant of -ul)

Added to an adjective to form an adverb.

Form of -il after the vowels Ö / Ü and a consonant other than L.

offspring, young (of an animal), young organism (animal or plant) (e.g., torül = young bull, bullock; kunül = young cow, heifer; lupül = wolf cub)

Hypocoristic or used to denote affection for the noun. (e.g., Samül = Sammy)

Source: wiktionary.org