[v] get better; "The weather improved toward evening." [v] to make better; "The editor improved the manuscript with his changes"
ameliorate, better, meliorate
aggravate, decline, exacerbate, exasperate, worsen
accommodate, acculturate, adapt, adjust, advance, alter, ameliorate, amend, apprentice, be changed, be converted into, be renewed, benefit, benefit from, best, better, boost, bottom out, brace up, break, break in, break up, breed, bring forward, bring up,