どうぞ固くならないで下さい。

please; kindly; I beg of you; by all means; feel free; you are welcome; here you are

hard; solid; tough; stiff; tight; wooden; unpolished (e.g. writing); strong; firm (not viscous or easily moved); safe; steady; honest; steadfast; obstinate; stubborn; bookish; formal; stuffy

be; is; indicates past or completed action; indicates light imperative

to give; to confer; to bestow; to kindly do for one; to oblige; to favour; to favor