[anrakushi]

it has a few meanings and can be used in different ways.. but here is the definition for Kuso:
糞 【くそ】 (int,n) (1) (col) feces; excrement; shit; bullshit; (adj-pn) (2) damn (adds emphasis and or annoyance to next word, e.g., damn hot, damn kids, etc.); damned

i use this word paired with 下手 (heta) bad/unskilled at something to mean i'm really bad. like if someone say to me you speak japanese really well, i would say まだ下手くそ - (madahetakuso) which means i still really lack skill, im still really bad at.

so it is not always used to translate in an "shit/damn" kind of way.

it is all on how it is used and pronounced as said before.