The phrase "water at mouth" typically means to crave or desire something intensely. There are several synonyms that can be used to convey this meaning, such as salivate, drool, or hunger. Other options include covet, yearn, or ache, which imply a longing or strong desire for something. Additionally, the phrase "mouth-watering" can be used to describe something that looks or smells delicious, further emphasizing the desire for it. Other synonyms that may be used in a similar context include lust, crave, and hanker, all of which suggest a strong and often uncontrollable desire for something.