J
jangle, wrangle, squabble, and quarrel
jealousy, suspicion, envy, and watchfulness
joyful, lively, happy, and hilarious
judgment, discrimination, penetration, and sagacity [sagacity = farsighted; wise]
just, impartial, equitable, and unbiased
juvenile, childish, trifling, and puerile [puerile = immature; childish]