when i say, most important of processes is photosynthesis, here 'most imp' is a noun

Your statement is an interesting observation about the role of photosynthesis in ecosystems and its importance in the context of biological processes. However, in the phrase "most important of processes," "most important" functions as an adjective that describes the noun "processes."

To clarify:

1. Phrase Structure: The phrase "most important of processes" contains the adjective "most important" which modifies the noun "processes."

2. Noun Function: In this context, "most important" is not a noun but rather an adjectival phrase highlighting the significance.

3. Redefining: To convey that "most imp" refers to a noun, you might say, "Photosynthesis is the most important process." Here, "the most important process" clearly identifies "process" as the noun being emphasized.

In summary, while you expressed a key concept regarding photosynthesis, it's essential to clarify the grammatical roles of adjectives and nouns in your statement. If you need any further grammatical analysis or examples, feel free to ask!