I'm not exactly sure how to state my question but I'll try my best. While reading a biography of Dante, I stumbled upon the word "guild." I took a look at www.freedictionary.com to find its meaning, and I found out by looking at the definitions that the word "guild" and the word "gild" can be used interchangeably when they are used as a noun. However, my questions would be, why can't the words be used interchangeably as a verb as well? Is there a rule in English that could explain why some words can be used interchangeably while they are used as nouns but not as verbs?
And lastly, just out of curiosity, are there any other words similar to "guild" and "gild" that can only be used interchangeably when they are nouns but not as verbs, or vice versa, that can be used interchangeably as verbs but not as nouns?
guild also gild (gĭld)
n.
1. a. An association of persons of the same trade or pursuits, formed to protect mutual interests and maintain standards.
b. A similar association, as of merchants or artisans, in medieval times.
2. Ecology A group of species in a community that use similar environmental resources in a similar way, such as a group of songbirds that all glean insects from leaves.
http://www.thefreedictionary.com/guild
gild (ɡɪld)
vb (tr) , gilds, gilding, gilded or gilt (ɡɪlt)
1. to cover with or as if with gold
2. gild the lily
a. to adorn unnecessarily something already beautiful
b. to praise someone inordinately
3. to give a falsely attractive or valuable appearance to
4. to smear with blood
[Old English gyldan, from goldgold; related to Old Norse gylla, Middle High German vergülden]
ˈgilder n
gild 2 (gĭld) n. Variant of guild.