ムチャクチャ Usually used about money:  outrageous fees or bills.   $$$
しからん(けしからん) Used only by really old people, who are disgusted by the ways of today’s youth. Like a really really strong and corrosive version of だらしくない!If you’re under 80, don’t use this or else you’ll sound like a total ass. OLD   PPP
(むちゃ) Someone who acts outrageously because they are not thinking of the consequences. Unlike the other words, it has a strong nuance of impulsive.
ばかげてる Close to むちゃ、 but ばかげてる has the nuance of ‘silly’ or ‘absurd’ rather than ‘impulsive.’ You can use both 無茶 and バカげてる about celebrity scandals, but you’d only use バカげてる about a performance artist with five marmots glued to his nipples. Absurd!
みっともない  (literally, “something that is difficult to look at “ or “I don’t want to see that!”) . . . see だらしない
だらしない Shame on you! (sounds like older person or parent scolding the kids of today). だらしない is stronger and more rude than みっともない. They usually apply to kids’ appearance (floppy haircuts, walking on the heels of your sneakers, pants too baggy, etc), but it can also be used about slobby or undignified behavior: eating food while walking, etc. Ironically, if you see a parent that is letting their kid yell in a movie theater / have a tantrum in a shopping mall, and the parent is just ignoring the kid, you can call  the PARENT  みっともない。