What is Abuse?

Legal Definition
Abuse is the improper usage or treatment of an entity, often to unfairly or improperly gain benefit. Abuse can come in many forms, such as: physical or verbal maltreatment, injury, assault, violation, rape, unjust practices; crimes, or other types of aggression.
-- Wikipedia
Legal Definition
1) Abuse, generally: physically, sexually, or mentally injuring a person.

2) Child abuse: physically, sexually, or mentally injuring a child either with intent or through neglect.

3) Substance abuse: excessively using or misusing a legal or illegal substance.

4) In bankruptcy: filing under chapter 7 by a debtor whose monthly, disposable income exceeds $10,950 or 25% of his or her non-priority unsecured debt (if at least $6,575) for a five-year period is presumptively abusive, requiring dismissal or conversion to chapter 13.
See also
Legal Definition
Every thing which is contrary to good order established by usage. Merl. Rep. h. t. Among the civilians, abuse has another signification; which is the destruction of the substance of a thing in using it. For example, the borrower of wine or grain, abuses the article lent by using it, because he cannot enjoy it without consuming it. Leg ; El. Dr. Rom. 414. 416.
-- Bouviers Law Dictionary
Legal Definition
v. To make excessive or improper use of a thing or to employ it in a manner contrary to the natural or legal rules for its use; to make an extravagant or excessive use, as to abuse one's authority. In the civil law, the borrower of a chattel which, in its nature, cannot be used without consuming it, such as wine or grain, is said to abuse the thing borrowed if he uses it.
-- Black's Law Dictionary
Legal Definition
n. Everything which is contrary to good order established by usage. Merl. Repert. Departure from use; immoderate or improper use. Of corporate franchises. The abuse or misuse of its franchises by a corporation signifies any positive act in violation of the charter and in derogation of public right, willfully done or caused to be done; the use of rights or franchises as a pretext for wrongs and injuries to the public. Baltimore v. Pittsburgh, etc., RCo., 3 Pittsb. R. (Pa.) 20, Fed. Cas No. 827; Erie & N. E. R. Co. v. Casey, 26 Pa. 287, 318 ; Railroad Commission v. Houston, etc., R. Co., 90 Tex. 340, 38 S. W. 750; People v. Atlantic Ave. R. Co., 125 N. Y. 513, 26 N. El 622.

Of judicial discretion. This term, commonly employed to justify an interference by a higher court with the exercise of discretionary power by a lower court, implies not merely error of judgment, but perversity of will, passion, prejudice, partiality or moral delinquency. The exercise of an honest judgment, however erroneous it may appear to be, is not an abuse of discretion. People v. New York Cent. It. Co., 29 N. Y. 418, 431; Stroup v. Raymond, 183 Pa. 279, 38 Atl. 626, 63 Am. St. Rep. 758; Day v. Donohue, 62 N. J. Law, 380, 41 Atl. 934; Citizens' St R. Co. v. Heath, 29 Ind. App. 395, 62 N. E. 107.

Where a court does not exercise a discretion in the sense of being discreet, circumspect, prudent, and exercising cautious judgment, it is an abuse of discretion. Murray v. Buell, 74 Wis. 14, 41 N. W. 1010; Sharon v. Sharon, 75 Cal. 1, 16 Pac. 345. Of a female child. An injury to the genital organs in an attempt at carnal knowledge, falling short of actual penetration. Dawkins v. State, 58 Ala. 376, 29 Am. Rep. 754.

But, according to other authorities, "abuse" is here equivalent to ravishment or rape. Palin v. State, 38 Neb. 862, 57 N. W. 743; Commonwealth v. Roosnell, 148 Mass. 32, 8 N. E. 747; Chambers v. State, 46 Neb. 447, 64 N. W. 1078.

Of distress. The using an animal or chattel distrained, which makes the distrainer liable as for a conversion. Of process. There is said to be an abuse of process when an adversary, through the malicious and unfounded use of some regular legal proceeding, obtains some advantage over his opponent. Wharton.

A malicious abuse of legal process is where the party employs it for some unlawful object, not the purpose which it is intended by the law to effect; in other words, a perversion of it. Lauzon v. Charroux, 18 R. I. 407, '28 Atl. 975; Mayer v. Walter, 64 Pa. 283; Bartlett v. Christhilf, 69 Md. 219, 14 Atl. 518; King v. Johnston, 81 Wis. 578, 51 N. W. 1011; Kline v. Hibbard, 80 Hun, 50, 29 N. Y. Supp. 807.
-- Black's Law Dictionary