prickly

from The American Heritage® Dictionary of the English Language, 5th Edition.

• adjective Having prickles.
• adjective Prickling or tingling or smarting.
• adjective Causing trouble or vexation; thorny.
• adjective Bristling or irritable.

from The Century Dictionary.

• Full of sharp points or prickles; armed with prickles: as, a prickly shrub.
• Pricking or stinging; noting the sensation of being pricked or stung.

from the GNU version of the Collaborative International Dictionary of English.

• adjective Full of sharp points or prickles; armed or covered with prickles.
• adjective (Med.) a noncontagious cutaneous eruption of red pimples, attended with intense itching and tingling of the parts affected. It is due to inflammation of the sweat glands, and is often brought on by overheating the skin in hot weather.
• adjective (Bot.) a name given to several plants of the cactaceous genus Opuntia, American plants consisting of fleshy, leafless, usually flattened, and often prickly joints inserted upon each other. The sessile flowers have many petals and numerous stamens. The edible fruit is a large pear-shaped berry containing many flattish seeds. The common species of the Northern Atlantic States is Opuntia vulgaris. In the South and West are many others, and in tropical America more than a hundred more. Opuntia vulgaris, Opuntia Ficus-Indica, and Opuntia Tuna are abundantly introduced in the Mediterranean region, and Opuntia Dillenii has become common in India.
• adjective (Bot.) a West Indian palm (Bactris Plumierana), the slender trunk of which bears many rings of long black prickles.
• adjective (Bot.) a West Indian cactaceous plant (Cereus triangularis) having prickly, slender, climbing, triangular stems.
• adjective (Zoöl.) any one of several species of South American burrowing rodents belonging to Ctenomys and allied genera. The hair is usually intermingled with sharp spines.

from Wiktionary, Creative Commons Attribution/Share-Alike License.

• adjective Covered with sharp points.
• adjective Easily irritated.

from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.

• adjective very irritable
• adjective having or covered with protective barbs or quills or spines or thorns or setae etc.