(What's with the HTML button?  I just tried to use <strikeout> and all I got was a blank panel.)

asusena Yerevan, Armenia said
Thanks Bob for correcting me....

<Chuckle> Are you being facetious?  I must watch that.

There's a story I keep around for the purpose of reminding myself:

Someone wrote: I was walking down the street the other day, and ran across a friend I hadn't seen in ten years.  While we were back-slapping and glad-handing, he asked me "How've you been?  I've missed not seeing you."

Well, no, I said; you've missed seeing me.  Not seeing me is what you've been doing.

"I meant what I said", he responded a little cooly, "but I'd forgotten until now just why."

I don't feel the same about star-gazing; I would happily go out to star-gaze at night, in another part of country.  I think both our reactions, including that we differ, confirm that they're based solely on ugliness, as you say, rather than some other factor.

But I see a problem wrong with your saying these are examples of conversion.  Above you defined "conversion" as turning one part of speech into another—a noun into a verb, an adjective into a noun and so on—but that isn't quite what's happening here.  "Gaze" is already a verb; "star-gaze" is just adding the object.  And "farm" may have originally been a noun that was later turned into a verb by "conversion", but that happened long before anyone started talking about fish-farming.

Bob Bridges said
Conversely "go" has no past tense; we say "went" instead (which I take it used to be the past tense of "wend", though we don't remember that now).

You are right about the simple past forms. Strictly speaking, the past participle gone is not gone, and it is past tense.

The term I have always heard for the English forms is defective. Other common examples of defective verbs in English are must / to have to, beware

Bob Bridges said

...
Unless—I just thought of this—it's the other verb "can", meaning to preserve.  Maybe the write intends to can peaches this afternoon.

...

The online Oxford English Dictionary (OED) has the noun, can, much earlier, a1000, than the verb form, 1861. This was a conversion which took a long time.

Unless—I just thought of this—it's the other verb "can", meaning to preserve.  Maybe the write intends to can peaches this afternoon.

Back in college, they taught us about "deponent" Greek verbs (my Greek teacher said the word originally meant "crippled", though I don't recognize that meaning in the Latin roots).  Deponent verbs are those that don't have all their forms; there may be no passive-voice form, or optative mood, whatever.  Someone who knows more about English grammar than I do may correct me, but I think of certain English words that way:  "Can", for example, has no subjunctive mood or future tense so if I want to change "we can do it" to the future I have to say "we will be able to do it".  Conversely "go" has no past tense; we say "went" instead (which I take it used to be the past tense of "wend", though we don't remember that now).

http://www.phil.muni.cz/plonedata/wkaa/BSE/BSE_1969-08_Scan/BSE_08_27.pdf

By saying conversion, I meant mostly grammatical conversion. 

Another example which  is more unacceptable for me and which I came across  is the use of [to can]. How is that possible to use modal auxiliary [can] as a simple verb?

As  far as [revenge] is concerned, I suppose that the verb [revenge] existed in the language long ago and  has  even got  a strong foothold in the language. Oxford Advanced Learners Dictionary (OALD, 2006:1300) provides us with the following data for [revenge] as a verb:

PHR V. revenge yourself on sb/  be revenged on sb (literary) to punish or hurt sb because they have made you suffer: She vowed to be revenged on them all.

 Moreover, OALD (2006:90) also has it that avenge is mostly used as a verb and revenge - as a noun. However, "in more formal and literary English revenge can also be used as a verb.

I think that this also a development of the linguistic sign and a constant change in the word-stock of the English language.

I don't mind coining new verbs, or adopting nouns or adjectives to fill in a gap.  But we already have a verb for this; it's "avenge".  The poor benighted ignorami who write this meant that such a one intends to avenge himself upon someone.

I have the same reaction (you've probably heard me complain about it already) to someone "reverencing" an ethical principle, or God.  In principle there's nothing wrong with turning a noun into a verb, but it's too late for this one; we can already revere God.  Same with "service" when we can "serve".  No doubt you'll think of others.