जिसमें रस न हो।

सूखे फल रसहीन होते हैं।
नीरस, बेरस, रसहीन, शुष्क, सूखा

Lacking juice.

juiceless

जिससे मन ऊब जाए या उबाने वाला।

उसका भाषण मेरे लिए उबाऊ था।
उकताऊ, उचाटू, उबाऊ, ऊबाऊ, पकाऊ

So lacking in interest as to cause mental weariness.

A boring evening with uninteresting people.
The deadening effect of some routine tasks.
A dull play.
His competent but dull performance.
A ho-hum speaker who couldn't capture their attention.
What an irksome task the writing of long letters is.
Tedious days on the train.
The tiresome chirping of a cricket.
Other people's dreams are dreadfully wearisome.
boring, deadening, dull, ho-hum, irksome, slow, tedious, tiresome, wearisome