a series of unexpected and unpleasant occurrences; "a rash of bank robberies"; "a blizzard of lawsuits" any red eruption of the skin imprudently incurring risk; "do something rash that he will forever repent"- George Meredith
overhasty in counsel or action; precipitate; resolving or entering on a project or measure without due deliberation and caution; opposed to prudent; said of persons; as, a rash statesman or commander
If you talk about a rash of events or things, you mean a large number of unpleasant events or undesirable things, which have happened or appeared within a short period of time. one of the few major airlines left untouched by the industry's rash of takeovers = spate. if you are rash, you do things too quickly, without thinking carefully about whether they are sensible or not foolish (Probably from an unrecorded rAsc)
marked by unthinking boldness; with defiant disregard for danger or consequences; "foolhardy enough to try to seize the gun from the hijacker"; "became the fiercest and most reckless of partisans"-Macaulay; "a reckless driver"; "a rash attempt to climb the World Trade Center"