Antonyms of verb lighten

2 of 6 senses of lighten

Sense 1
lighten, lighten up, buoy up -- (make more cheerful; "the conversation lightened me up a bit")
       Antonym of weigh down (Sense 1)
      => weigh down, weigh on -- (be oppressive or disheartening to)

Sense 5
lighten, lighten up -- (become lighter; "The room lightened up")
       Antonym of darken (Sense 1)
      => darken -- (become dark or darker; "The sky darkened")

Synonyms/Hypernyms (Ordered by Estimated Frequency) of verb lighten

6 senses of lighten

Sense 1
lighten, lighten up, buoy up -- (make more cheerful; "the conversation lightened me up a bit")
       => cheer -- (show approval or good wishes by shouting; "everybody cheered the birthday boy")

Sense 2
lighten -- (reduce the weight on; make lighter; "she lightened the load on the tired donkey")
       => unburden, disburden -- (take the burden off; remove the burden from; "unburden the donkey")

Sense 3
lighten, lighten up, buoy up -- (become more cheerful; "after a glass of wine, he lightened up a bit")
       => cheer, cheer up, chirk up -- (become cheerful)

Sense 4
brighten, lighten up, lighten -- (make lighter or brighter; "The paint will brighten the room")
       => change, alter, modify -- (cause to change; make different; cause a transformation; "The advent of the automobile may have altered the growth pattern of the city"; "The discussion has changed my thinking about the issue")

Sense 5
lighten, lighten up -- (become lighter; "The room lightened up")
       => change -- (undergo a change; become different in essence; losing one's or its original nature; "She changed completely as she grew older"; "The weather changed last night")

Sense 6
relieve, lighten -- (alleviate or remove (pressure or stress) or make less oppressive; "relieve the pressure and the stress"; "lighten the burden of caring for her elderly parents")
       => mitigate -- (make less severe or harsh; "mitigating circumstances")