fear

1 fear /ˈfiɚ/ noun
plural fears
1 fear
/ˈfiɚ/
noun
plural fears
Britannica Dictionary definition of FEAR
1 
: an unpleasant emotion caused by being aware of danger : a feeling of being afraid
[noncount]
[count]
◊ If you are in fear of your life or (US) in fear for your life, you are afraid of being killed.
2 
[noncount] : a feeling of respect and wonder for something very powerful
◊ To put the fear of God into someone is to frighten someone very badly.

no fear

British, informal
— used in speech to say that there is no reason to be afraid or worried
fear , dread , alarm , and fright mean painful emotion felt because of danger.
fear is the most general word and suggests a continuing emotional state.
dread suggests a strong feeling of not wanting to accept or deal with something bad or unpleasant.
alarm may suggest a strong emotion caused by an unexpected or immediate danger.
fright suggests a feeling caused by something unexpected and often suggests a brief emotion.
2 fear /ˈfiɚ/ verb
fears; feared; fearing
2 fear
/ˈfiɚ/
verb
fears; feared; fearing
Britannica Dictionary definition of FEAR
1 
[+ object] : to be afraid of (something or someone)
— sometimes followed by to + verb
2 
[+ object] : to expect or worry about (something bad or unpleasant)
◊ The formal phrase I fear is used when you are worried that something bad or unpleasant has happened or is true.
3 
[no object] : to be afraid and worried
4 
[+ object] : to feel respect and wonder for something very powerful

fear for

[phrasal verb]
fear for (something or someone)
: to feel concern for (something or someone) : to worry about (something or someone)