`daw` and `diw` deletes a whole word (unlike `dw` which only deletes forward). They differ in what they do with whitespace; `aw` also trims trailing whitespace (or leading whitespace if there's no trailing) while `iw` leaves the whitespace alone. These two are text objects that can be combined with other commands and quantifiers, so that `yaw` copies a word without deleting it, or `d2aw` deletes two words.
Wrapping in parens requires the vim-surround plugin, but with that installed you can do `ysaw(` and `ysaw)` to wrap in parens (also works with brackets and curlies and such), either with spaces inside the parens (the former) or snugly around the word (the latter).