adjectives
not firm or firmly fixed; likely to fail or give way
"the hinge is insecure"
see also
not firmly placed or set or fastened
lacking in security or safety
"his fortune was increasingly insecure"; "an insecure future"
lacking self-confidence or assurance
"an insecure person lacking mental stability"
is similar to
anxious or nervous to an excessive degree
is similar to
lacking boldness or confidence