The adverbs यूँ and यों express manner.
They can be translated into English as “in this manner”, “in such a manner”, “in this way”, etc.
उसने मुझे यों देखा कि मुझे उससे डर लगा – “He looked at me in such a way that I became scared of him!”
These adverbs are somewhat emphatic.
They are used in a variety of idioms also.
The idiom यूँ + ही means “for no particular reason”:
मैं यूँ ही दुकान को चला गया – “I just went to the store for no reason really”
The adverb ऐसे is also used with ही to express “just like that”, “for no particular reason”, etc: बच्चा ऐसे ही रो रहा था – “The child was crying for no reason”.
यूँ ही can also express “simply”, “effortlessly”, “easily”, etc:
उसने बहुत भारी डिब्बा यूँ ही उठा लिया – “He lifted a very heavy case easily”