v. cause to be bitter or resentful; "These injustices embittered her even more"

v. make worse; "This drug aggravates the pain"

v. make the chemically affected part of (a negative) denser or more opaque in order produce a stronger contrast between light and dark

v. add poison to; "Her husband poisoned her drink in order to kill her"

v. make sharp or sharper; "sharpen the knives"

v. furnish with a grate; "a grated fireplace"

v. make sour or more sour