In any trade, it’s necessary to have the correct tools.
Writing poetry without a dictionary is an errand for fools.
Webster is my go-to choice—I have more than one edition.
My favorite is a 1934 unabridged in so-so condition.

This monster was spotted while riding with a friend in St. Paul,
  where below a pile of refuse, I discovered the haul.
For picking through the trash, I was ridiculed to great measure,
  but I have never regretted rescuing this literary treasure.

The massive reference is the go-to when I get stumped,
  but I don’t lift it much, lest my back get humped.
The pages are thin and filled with words, words galore.
As far as dictionaries go, I could not ask for anything more!

If you don’t recognize a word, look it up for heaven’s sake.
With a dictionary at hand, it’s worth the moment it will take.
For those who are down or on an emotional fence,
  expressive, supportive words can have a positive influence.