reverse engineering

skill (capacity to do something well)

to use / to employ / to make use of, to apply / to spend

software / video game

function (as something), work

a function

he / distal demonstrative, something far off removed from both speaker and listener: that / boyfriend

distal demonstrative, something far off removed from both speaker and listener: that, yon / particularly, male personal third person pronoun: he / by extension from he: boyfriend

he; boyfriend

the action of taking something apart in order to study it; analysis / (mathematics) analysis