ambiguous

adj. open to dispute, having many possible interpretations; obscure, vague

Ambiguity is the property of words, terms, notations and concepts (within a particular context) as being undefined, undefinable, or without an obvious definition and thus having an unclear meaning. A word, phrase, sentence, or other communication is called “ambiguous” if it can be interpreted in more than one way. Ambiguity is distinct from vagueness, which arises when the boundaries of meaning are indistinct. Ambiguity is in contrast with definition, and typically refers to an unclear choice between standard definitions, as given by a dictionary, or else understood as common knowledge.
See more at Wikipedia.org...

Adjective
1. open to two or more interpretations; or of uncertain nature or significance; or (often) intended to mislead; "an equivocal statement"; "the polling had a complex and equivocal (or ambiguous) message for potential female candidates"; "the officer's equivocal behavior increased the victim's uneasiness"; "popularity is an equivocal crown"; "an equivocal response to an embarrassing question"
(synonym) equivocal
(similar) ambivalent
2. having more than one possible meaning; "ambiguous words"; "frustrated by ambiguous instructions, the parents were unable to assemble the toy"
(antonym) unambiguous
(similar) double-barreled, double-barrelled
(see-also) equivocal
3. having no intrinsic or objective meaning; not organized in conventional patterns; "an ambiguous situation with no frame of reference"; "ambiguous inkblots"
(similar) unstructured
(classification) psychology, psychological science

(a.)
Doubtful or uncertain, particularly in respect to signification; capable of being understood in either of two or more possible senses; equivocal; as, an ambiguous course; an ambiguous expression.
  

cheng2 ye3 xiao1 he2, bai4 ye3 xiao1 he2
Both done and undone by Xiao He.
Meaning that both the success and the failure of something was caused by one and the same person.