timid and lacking confidence
timorous - timid
‘Timorous’ is derived from the Latin word for ‘fearful', but it expresses a particular type of fear - one that comes from a lack of assertiveness and self-esteem. That means that it tends to manifest itself particularly in social anxiety, such as when having to give a speech or mingle with others. Always used in a negative context.
In just the few months she has been working here, Lucy has gone from a timorous new recruit who was too shy to talk to anyone, to one of the most popular members of staff.
Problems in society are being exacerbated by the timorousness of our politicians. They are simply too afraid to do anything to address the issues.
You need to learn to be comfortable interacting with your colleagues in a social environment instead of cowering timorously in the corner at work functions.