Three questions...

I have a few seemingly trivial questions I was hoping someone could answer:

1.  What is the opposite of the word earg?  I know there are words with opposite meanings, such as beald, ellenheard, caf, etc.  But is there a word that was consistently employed as its opposite?  For example, if I asked an English speaker what the opposite of "happy" is, I would expect him to respond with the word "sad," and not "melancholy," "depressed," or "gloomy," even though the latter all mean "sad."  If I could ask and Old English speaker what the opposite of earg is, what would he say?  Are there examples in Old English texts of a word that is consistently used in opposition to earg?

2.  Same question, except this time the word is idel.

3.  The word ellen is a noun.  Is there a corresponding adjectival form of ellen?  I know of compound adjectives like ellenheard and ellenrof.  The simplest adjective form I can find is ellenlic, but is there anything simpler, that is, something based directly off the noun without any suffixes added?  I was thinking of something like "elne" or the word ellen itself being used as an adjective.  Are there examples in Old English of the word being used this way, or is ellen used almost exclusively as a noun?

Thanks in advance for your answers.