What is Due Care?

Legal Definition
Just, proper, and sufficient care, so far as the circumstances demand it; the absence of negligence. This term, as usually understood in cases where the gist of the action is the defendant's negligence, implies not only that a party has not been negligent or careless, but that he has been guilty of no violation of law in relation to the subject-matter or transaction which constitutes the cause of action.

Evidence that a party is guilty of a violation of law supports the issue of a want of proper care ; nor can it be doubted that in these and similar actions the averment in the declaration of the use of due care and the denial of it in the answer, properly and distinctly put in issue the legality of the conduct of the party as contributing to the accident or injury which forms the groundwork of the action , No specific averment of the particular unlawful act which caused or contributed to produce the result complained of should, in such cases, be deemed necessary. See Ryan v. Bristol, 63 Conn. 26, 27 Atl. 309 ; Paden v. Van Blarcom, 100 Mo. App 185, 74 S. W. 124; Joyner v. Railway Co.., 26 S. C. 49, 1 S. E. 52; Nicholas v. Peck, 21 R. I. 404, 43 Atl 1038; Railroad Co. v. Yorty, 158 III. 321, 42 N. E 64Schmidt v. Sinnott, 103 111. 165; Butterfield v. Western R. Corp., 10 Allen (Mass.) 532, 87 Am. Dec. 678; Jones v. Andover, 10 Allen (Mass.) 20
-- Black's Law Dictionary
Legal Definition
Care such as an ordinarily prudent man would have exercised under the circumstances. See 70 N. H. 441, 55 L. R. A. 426, 50 Atl. 146.
-- Ballentine's Law Dictionary