a- in the state or process of

kin: 家人(和亲戚). kinsman, kinswoman, kinsfolk, kinship

kith and kin: friends and family

Sometimes 'next of kin' refers to the person who is someone's closest relative, especially in official or legal documents.

So, alike and akin are alike and akin.

ail: old-fashioned to be ill, or to make sb feel ill or unhappy，恐怕就是ill的两种拼法。偏激地说，这个词是编词汇大纲的人想显摆下自己的词汇量吧？学英语和学英美文学两码事，英美文学和19世纪名著不是同义词。ail和ale发音一样，恐怕黑暗料理国的酒也不咋样…… 'Eew!' said when one sees something disgusting.

c. 1300, from Old English eglan "to trouble, plague, afflict," from Proto-Germanic *azljaz (source also of Old English egle "hideous, loathsome, troublesome, painful;" Gothic agls "shameful, disgraceful," agliþa "distress, affliction, hardship," us-agljan "to oppress, afflict"), from PIE *agh-lo-, suffixed form of root *agh- (1) "to be depressed, be afraid." Related: Ailed; ailing; ails. From late Old English also of mental states and moods.