WordNet sense 1 (special emphasis attached to something):

focus

WordNet sense 2 (difficulty that causes worry or emotional tension):

strain

WordNet sense 3 ((psychology) a state of mental or emotional strain or suspense):

tenseness, tension

WordNet sense 4 (the relative prominence of a syllable or musical note (especially with regard to stress or pitch)):

accent, emphasis, accent

WordNet sense 5 (test the limits of):

try

WordNet sense 6 (to stress, single out as important):

accentuate, emphasize, punctuate, emphasise