Jin : Metal ke Phobia ko Kya bolte hai ?
Jk : Firse nhi... *About to leave*
Jimin : Kya bolte hai ?
Jin : Metallurgy! *Window wiping laughter*
JIMIN : *can't see anything cuz he is laughing*
Namjoon : *Breaks the table* BAS ABH BOHOT HO GAYA!
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Those who don't know what Metallurgy means here is the meaning
(the branch of science and technology concerned with the properties of metals and their production and purification.)
But The joke is Stressing more on Pronunciation than the meaning Of Metallurgy.(original)