唯

only / alone / -ism (in Chinese, a prefix, often combined with a suffix such as 主義|主义[zhu3 yi4] or 論|论[lun4], e.g. 唯理論|唯理论[wei2 li3 lun4], rationalism)

yes

mouth / classifier for things with mouths (people, domestic animals, cannons, wells etc) / classifier for bites or mouthfuls

short-tailed bird