In boxing, jab is a type of a punch at the opponent. “People with excellent jabs have calm and relaxed jabs that hit like a small spark of power and hit very accurately. Jabs can be made stronger by stepping forward, or using proper timing with proper footwork and effective angles.” –expertboxing.com
Governments, and medical experts recommend people to take jabs (vaccinations) as a preventive care against some diseases especially when one is travelling outside his or her country.
Jab functions as a noun and verb. Jab means to pierce, to stab such as getting a jab from the doctor; poking, prodding, thrusting someone such as with a hand gesture like a blow but not with the force of a blow, and touching someone suddenly with the hand or elbow.
EXAMPLE: Some people jab at their companions during conversations, and they could be jabberers, too.
Jabber means to talk in a noisy, rapid, excited, declamatory way; and jabber is a noun, and a verb.
Jabberer is the one who talks a lot especially about trivial things, drivelling about this and that like a driveller.
The derivatives of jab are jabs, jabbed (verbs), jabbing (verb & noun), jabber (noun and verb), jabberingly (adverb), and jabberment (archaic variant of jabber the noun).
Jabberwock or jabbernowl is the dreaded monster with blazing eyes as mentioned by Lewis Carroll in ‘Through the Looking Glass’.
Jamb is a part of the window or door or fireplace that is a side post or surface; the upright side of an opening such as a door or window; the board that forms the side of a door or window, the side-post.
“If you rap your knuckles against a window jamb or door, if you brush your leg against a bed or desk, if you catch your foot in a curled-up corner of a rug, or strike a toe against a desk or chair, go back and repeat the sequence. You will find yourself surprised how far off course you were to hit that window jamb, that door, that chair. Get back on course and do it again. How can you pilot a spacecraft if you can’t find your way around your own apartment?” –William S. Burroughs
Jamb is derived from Old French word ‘jambe’ referring to a leg, or vertical support which is indeed derived from Greek word ‘kampe’ meaning a joint. A doorjamb or doorpost is the vertical portion of the door frame into which a door or window is fitted or secured, and the jamb bears the weight through its hinges.
People even jabber about this and that being in a Jacuzzi (Jacuzzi is a whirlpool bath, and a trademark named after its inventors, Roy and Candido Jacuzzi), or leaning on their doorjambs.