The udep relation is used for complements when one does not wish to or is unable to distinguish between arguments and modifiers. This relationship can notably be used in cases where the complement’s relationship with its governor is ambiguous. When there is little debate about the nature of the relationship, the more specific label is preferred.

The governor and the dependent of a udep relation can have any POS. The udep relation is frequently given to the complements of nouns, since it is generally more difficult to distinguish between arguments and modifiers for nouns than it is for verbs.

As shown in the correspondences between SUD and UD, the udep label is used while automatically converting an obl label from a UD annotation. This is because obl can correspond to both comp:obl and mod in SUD.