“That su-u-ucks!” Crossword Clue

 The answer to the crossword clue "That su-u-ucks!" is SUCK. This is an informal exclamation of disappointment or frustration. It can also be used as a verb, meaning to draw something into the mouth or another opening with a sucking motion.

Here are some other words that can be used to complete the crossword clue "That su-u-ucks!":

Blows

Sucks

Sucks big time

Terrible

Awful

Horrible

Disastrous

Terrible

Dreadful

Lousy

Atrocious

I hope this helps!