noun
unskillfulness; lack of skill; inexperience
Abstract noun describing a state of being unskilled or inexperienced. Often used in formal or written contexts.
不熟練が原因で、作業に時間がかかった。
The work took a long time due to unskillfulness.
不慣れ means 'unaccustomed' or 'unfamiliar' with a situation or task, emphasizing lack of experience rather than lack of skill.
Formed from the prefix 不 (fu-, 'not') and 熟練 (jukuren, 'skill, proficiency'). The exact historical derivation is uncertain, but the components are transparent.