precociously

Example:The teenager was behaving immaturity by skipping school and spending days locked in his room.

Definition:In a way that shows lack of proper mental or emotional development; undeveloped, unripe; characterized by lack of adult qualities, emotions, or mannerisms.

Example:She arrived late to the event, missing the opening speech entirely.

Definition:Of or relating to a later time than one within the present or expected period, or than another specified or implied time.

Example:His cognitive function became retarded, and he was unable to perform even simple tasks.

Definition:Developed or made to develop more slowly than is natural, usual, or expected; characterized by mental or physical delays.