unskilled, bad at, poor at, weak at, incompetent / superficial, halfhearted, half-assed, careless / smaller or lesser in degree

a mistake, a poor result, a screwup

to make a mistake, to screw up

humble

the lower part, especially downstream or downwind / someone at a disadvantage or lower relative to another person, in terms of rank or ability

downstream; the lower portion of a slope / (theater) downstage, specifically the left side of the stage as viewed from the audience

(uncommon) cheap, low-quality goods

(uncommon) someone of low status or rank

(uncommon) to lower one's hand onto something, to set one's hand onto something

if done badly / perhaps