Jank is smell.
Jank is a thing that creeps slowly, insidiously into your projects. It happens in little bits and pieces at first: a corner cut here, a mistake swept under the rug there.
Jank is a product of compromises. All projects involve compromises, of course, decisions that balance competing goals against each other, a little from this, a little from that. These are not jank. Jank is the compromise that you make between doing the job fast and doing the job right. Jank is the 2 AM call you make because fuck it I'm tired and no one will ever know.
Jank festers. Jank grows. Over the long ages, jank spreads. In the end, jank will eat you alive.
Jank is a wager you made, mortgaging the future for the sake of the present. But eventually the future comes due; eventually all debts must be paid.
Jank catches up to you. You cannot run: your legs have become jank, rooted to the spot stronger than an oak tree. You cannot fight: your weapons have become jank, no longer your servants but your shackles. You cannot think: your mind has become jank, ossified and paralyzed to the very core.
Do not make jank.