Freebase(0.00 / 0 votes)Rate this definition: Diltiazem. Diltiazem is a nondihydropyridine member of the class of drugs known as calcium channel blockers, used in the treatment of hypertension, angina pectoris, and some types of arrhythmia. It is also an effective preventive medication for migraine. It is a class 3 antianginal drug, and a class IV antiarrhythmic.
Rigid definition, stiff or unyielding; not pliant or flexible; hard: a rigid strip of metal. See more.
Learner's definition of STIFF. [+ object] US, informal. : to not give as much money as you should give to (someone) He stiffed the waiter on the tip. [=he didn't give the waiter a tip or he gave a tip that was too small]