WordNet sense 1 (fearful expectation or anticipation):

apprehensiveness, dread

WordNet sense 2 (painful expectation):

misgiving

WordNet sense 3 (the cognitive condition of someone who understands):

discernment, savvy, understanding

WordNet sense 4 (the act of apprehending (especially apprehending a criminal)):

arrest, catch, collar, pinch, taking into custody