1. To make highly efficient, either in time or space, often at the expense of
clarity. "I managed to bum three more instructions out of that code." "I spent
half the night bumming the interrupt code." In elder days, John McCarthy
(inventor of Lisp) used to compare some efficiency-obsessed hackers among his
students to "ski bums"; thus, optimisation became "program bumming", and
eventually just "bumming".
2. To squeeze out excess; to remove something in order to improve whatever it
was removed from (without changing function; this distinguishes the process from
3. A small change to an algorithm, program, or hardware device to make it more
efficient. "This hardware bum makes the jump instruction faster."
Usage: now uncommon, largely superseded by v. tune (and tweak, hack), though
none of these exactly capture sense 2. All these uses are rare in Commonwealth
hackish, because in the parent dialects of English "bum" is a rude synonym for
bulletin board system « bulletproof « Bull
Information Systems « bum » bump » burble »
Bureau International des Poids et Mesures