Personally, I've heard 'crack' be used as a catchall term for 'shit that fucks your shit the fuck up', ie particularly powerful drugs such as meth and crack cocaine.
'Crackhead' can also be used a blanket term for 'he who dabbles in some fucked-up shit', not necessarily someone who exclusively smokes crack.
'Crackhead' can also be used a blanket term for 'he who dabbles in some fucked-up shit', not necessarily someone who exclusively smokes crack.
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