nifty - Particularly good, skillful, or effective
scrub - Rub (someone or something) hard so as to clean them, typically with a brush and water.
stuffy - (of a place) lacking fresh air or ventilation
bleak - (of an area of land) lacking vegetation and exposed to the elements
bravado - A bold manner or a show of boldness intended to impress or intimidate
jittery - Nervous or unable to relax
frail - (of a person) weak and delicate
smug - Having or showing an excessive pride in oneself or one's achievements
swap - To give something and be given something else instead
mellow - (especially of sound, taste, and color) pleasantly smooth or soft; free from harshness
obstacle - Something that blocks your way so that movement or progress is prevented or made more difficult.
scuzzy - Dirty and unpleasant