役不足 (yakubusoku) is one of the most misused Japanese words by native speakers. If you notice that your Japanese friends use this word in the wrong way, you can enlighten them with the correct definition described below.
If a position or job is 役不足 for a person, that means he/she is overqualified for it. For instance, a background actor is definitely yakubusoku for Hollywood stars. This word can also describe when over-engineered or extravagant things are used as a sledgehammer to crack a nut, as in “このハイテクな掃除機を狭い部屋に使うのは役不足だ” meaning “It is overkill if you use this high-tech vacuum cleaner in a small room”.
Misuse of 役不足
役不足 is one of the most misused Japanese words by native speakers. According to the survey conducted by 文化庁 (Agency for Cultural Affairs), only 40.3 % of Japanese people recognise its correct meaning described above, whereas 50.3 % of people misinterpret 役不足 as the opposite meaning, that is “someone is underqualified”. In particular, they often use it to sound modest when they feel they are underqualified for a job or position. In this case, they are likely to confuse it with “力不足“, which means “do not have enough skills/abilities to do something”.
Therefore, remember that 役不足 is used to describe something that is too trivial for a high-level person or thing, while 力不足 is used to describe a person who lacks enough skills/abilities to do something. Therefore, it is fine to use 力不足 to describe yourself, but not 役不足 unless you’re very confident in yourself.
役不足 consists of the two words, “役” meaning “role/position” and “不足” meaning “shortage/not enough”. Therefore, 役不足 describes a role that is not important enough for a high-level person or thing. However, many people misinterpret that it would describe a person who does not have enough experience or abilities to fulfil a role.
Such boring work would be too trivial for him.
MacBook ProをYouTube やTwitterだけの為に使うのは役不足だ
It is overkill if you use MacBook Pro just to browse YouTube or Twitter.
Ex3 [Wrong Usage]
I am underqualified for such important work.
(Note) To correct this sentence, 役不足 should be replaced with 力不足.
Synonyms: もったいない (mottainai; one’s ability is not utilised properly)
Synonyms in English: overkill, too trivial, a thing for which one is overqualified,
Related words and phrases: 力不足 (not have enough ability)