OVEREXTEND
overstrain, overextend
(verb) strain excessively; “He overextended himself when he accepted the additional assignment”
Source: WordNet® 3.1
Etymology
Verb
overextend (third-person singular simple present overextends, present participle overextending, simple past and past participle overextended)
To expand or extend to an excessive degree, especially to do so beyond a safe limit.
(linguistics, transitive) To apply (a term) to too many referents, by overextension.
(chess, transitive) To push a pawn too far, so that it becomes vulnerable to the opponent's attacks.
Source: Wiktionary