Ablutophobia: Fear of bathing or cleaning
Regardless of the fact that it is a real and serious phobia, you probably don't want to sit down next to someone with ablutophobia.
To be clear, ablutophobia is much more serious than hygiene routines that leave something to be desired. Ablutophobia is being afraid of showering. So, while a lot of us might procrastinate on that shampoo, we usually do not experience serious anxiety at the idea of it.
It is common that children experience a fear and aversion to bathing at a young age, and sometimes this fear can follow them into adulthood. Other times, the fear can arise from a specific event - maybe a relative fell in the shower and you are afraid of the same thing happening to you, or the shower scene in "Psycho" really freaked you out.
Ablutophobia is a very important fear to sort out, because not practicing good hygiene can lead to problems in social settings.