I will bite my thumb at them; which is a disgrace to them, if they bear it.
biting the thumb (placing the thumb nail behind the upper teeth and flicking it forward) was a highly insulting gesture in 16th-century Italy and England.
What sets it off matters more than it seems. Watch Sampson shift control - he aims to pull the Montagues into motion before he moves. Blame must land elsewhere, never on him.
I will take the wall of any man or maid of Montague's.
In Elizabethan cities, the person walking closest to the wall stayed out of the filth and sewage in the gutters
Claiming space by standing against the wall, Sampson asserts a higher position. His move reveals that the old conflict goes beyond open fights - dominance plays out through small acts each day. Public areas become quiet battlegrounds where status is tested without words.
Sampson. Gregory, o' my word, we'll not carry coals.
"Carry coals" was a slang term for enduring insults or doing dirty work. A "collier" is a coal-miner.