doubtfulness doubtfulness /ˈdaʊtˌfʊlnəs/

noun

1. Uncertainty about the truth, factuality or existence of something  ( doubtfulness , dubiousness , doubt , question )
   uncertainty about the truth, factuality or existence of something
    The dubiousness of his claim
   the dubiousness of his claim
    There is no question about the validity of the enterprise
   there is no question about the validity of the enterprise
   
   
2. The state of being unsure of something  ( doubtfulness , dubiety , dubiousness , doubt , incertitude , uncertainty )
   the state of being unsure of something
   

 nucleon nucleon /ˈnjuːkliɒn/

noun

1. A constituent (proton or neutron) of an atomic nucleus  ( nucleon )
   a constituent (proton or neutron) of an atomic nucleus
   
   

 imitation imitation /ˌɪməˈteɪʃən/

adjective

1. () Not genuine or real; being an imitation of the genuine article  ( fake , false , faux , imitation , simulated )
   not genuine or real; being an imitation of the genuine article
    It isn't fake anything; it's real synthetic fur
   it isn't fake anything; it's real synthetic fur
    Faux pearls
   faux pearls
    False teeth
   false teeth
    Decorated with imitation palm leaves
   decorated with imitation palm leaves
    A purse of simulated alligator hide
   a purse of simulated alligator hide
   

noun

1. () The doctrine that representations of nature or human behavior should be accurate imitations  ( imitation )
   the doctrine that representations of nature or human behavior should be accurate imitations
   
2. () Copying (or trying to copy) the actions of someone else  ( imitation )
   copying (or trying to copy) the actions of someone else
    Children often show their admiration through imitation of their parents.
   Children often show their admiration through imitation of their parents.
   
   
3. () Something copied or derived from an original  ( imitation )
   something copied or derived from an original
     The necklace was made of imitation pearls.
   The necklace was made of imitation pearls.
   
   
4. A representation of a person that is exaggerated for comic effect  ( caricature , imitation , impersonation )
   a representation of a person that is exaggerated for comic effect
   
   

 sinus sinus /ˈsaɪnəs/

noun

1. A wide channel containing blood; does not have the coating of an ordinary blood vessel  ( sinus , venous sinus )
   a wide channel containing blood; does not have the coating of an ordinary blood vessel
   
2. Any of various air-filled cavities especially in the bones of the skull  ( sinus )
   any of various air-filled cavities especially in the bones of the skull
    The sinuses are air-filled cavities in the skull that help to filter and humidify air
   The sinuses are air-filled cavities in the skull that help to filter and humidify air
   
   
3. An abnormal passage leading from a suppurating cavity to the body surface  ( fistula , sinus )
   an abnormal passage leading from a suppurating cavity to the body surface