designate equivalent words from ui

[ben-schulz]

i'd like to be able to designate equivalent words from the ui, so that it is easier to group things on the fly.

for example, i'd like to identify that climb and climbing refer to the same type of action, as in:

"he was climbing the mountain"

and

"they climbed down the hill"

(this probably opens a separate question of: in what cases should climb and climbing be distinguished a words? but I would rather leave this open to the operator to decide.)