The four letter word you are looking for beginning with F that means in search of is 'find'. The meaning of find is summed up as according to the dictionary as to come upon, often by accident; meet with. There are a number of definitions the dictionary also says which are summed up below.
2. To come upon or discover by searching or making an effort: Found the leak in the pipe.
3. To discover or ascertain through observation, experience, or study: Found a solution; find the product of two numbers; found that it didn't really matter.
4a. To perceive to be, after experience or consideration: Found the gadget surprisingly useful; found the book entertaining.
B. To experience or feel: Found comfort in her smile.
5. To recover (something lost): Found her keys.
6. To recover the use of; regain: Found my voice and replied.
7. To succeed in reaching; arrive at: The dart found its mark.
8. To obtain or acquire by effort: Found the money by economising.
9. To decide on and make a declaration about: The jury deliberated and found a verdict of guilty. All the jurors found him guilty.
10. To furnish; supply.
11a. To bring (oneself) to an awareness of what one truly wishes to be and do in life.
B. To perceive (oneself) to be in a specific place or condition: Found herself at home that night; found himself drawn to the stranger.
V.intr. To come to a legal decision or verdict: The jury found for the defendant.
1. The act of finding.
2. Something that is found, especially an unexpectedly valuable discovery: The Rosetta stone was a providential archaeological find.
Phrasal Verb:
Find out
1. To ascertain (something), as through examination or inquiry: I found out the phone number by looking it up. If you're not sure, find out.
2. To detect the true nature or character of; expose: Liars risk being found out.
2. To come upon or discover by searching or making an effort: Found the leak in the pipe.
3. To discover or ascertain through observation, experience, or study: Found a solution; find the product of two numbers; found that it didn't really matter.
4a. To perceive to be, after experience or consideration: Found the gadget surprisingly useful; found the book entertaining.
B. To experience or feel: Found comfort in her smile.
5. To recover (something lost): Found her keys.
6. To recover the use of; regain: Found my voice and replied.
7. To succeed in reaching; arrive at: The dart found its mark.
8. To obtain or acquire by effort: Found the money by economising.
9. To decide on and make a declaration about: The jury deliberated and found a verdict of guilty. All the jurors found him guilty.
10. To furnish; supply.
11a. To bring (oneself) to an awareness of what one truly wishes to be and do in life.
B. To perceive (oneself) to be in a specific place or condition: Found herself at home that night; found himself drawn to the stranger.
V.intr. To come to a legal decision or verdict: The jury found for the defendant.
1. The act of finding.
2. Something that is found, especially an unexpectedly valuable discovery: The Rosetta stone was a providential archaeological find.
Phrasal Verb:
Find out
1. To ascertain (something), as through examination or inquiry: I found out the phone number by looking it up. If you're not sure, find out.
2. To detect the true nature or character of; expose: Liars risk being found out.