Antonyms of adj confident

3 senses of confident

Sense 1
confident (vs. diffident) -- (having or marked by confidence or assurance; "a confident speaker"; "a confident reply"; "his manner is more confident these days"; "confident of fulfillment")

diffident (vs. confident), shy, timid, unsure -- (lacking self-confidence; "stood in the doorway diffident and abashed"; "problems that call for bold not timid responses"; "a very unsure young man")

Sense 2
convinced (predicate), positive (predicate), confident (predicate) -- (persuaded of; very sure; "were convinced that it would be to their advantage to join"; "I am positive he is lying"; "was confident he would win")

INDIRECT (VIA certain, sure) -> uncertain, unsure, incertain -- (lacking or indicating lack of confidence or assurance; "uncertain of his convictions"; "unsure of himself and his future"; "moving with uncertain (or unsure) steps"; "an uncertain smile"; "touched the ornaments with uncertain fingers")
INDIRECT (VIA certain, sure) -> uncertain, unsure, incertain -- (lacking or indicating lack of confidence or assurance; "uncertain of his convictions"; "unsure of himself and his future"; "moving with uncertain (or unsure) steps"; "an uncertain smile"; "touched the ornaments with uncertain fingers")

Sense 3
confident, surefooted, sure-footed -- (not liable to error in judgment or action; "most surefooted of the statesmen who dealt with the depression"- Walter Lippman; "demonstrates a surefooted storytelling talent"- Michiko Kakutani)

INDIRECT (VIA capable) -> incapable -- ((followed by `of') lacking capacity or ability; "incapable of carrying a tune"; "he is incapable of understanding the matter"; "incapable of doing the work")

Similarity of adj confident

3 senses of confident

Sense 1
confident (vs. diffident) -- (having or marked by confidence or assurance; "a confident speaker"; "a confident reply"; "his manner is more confident these days"; "confident of fulfillment")
       => assured -- (marked by assurance; exhibiting confidence; "she paints with an assured hand")
       => cocksure, overconfident, positive -- (marked by excessive confidence; "an arrogant and cocksure materialist"; "so overconfident and impudent as to speak to the queen"; "the less he knows the more positive he gets")
       => reassured -- (having confidence restored; freed from anxiety; "reassured by her praise he pressed on")
       => self-assured, self-confident -- (showing poise and confidence in your own worth; "hardly more than a boy but firm-knit and self-confident")

Sense 2
convinced (predicate), positive (predicate), confident (predicate) -- (persuaded of; very sure; "were convinced that it would be to their advantage to join"; "I am positive he is lying"; "was confident he would win")
       => certain (predicate) (vs. uncertain), sure (vs. unsure) -- (having or feeling no doubt or uncertainty; confident and assured; "felt certain of success"; "was sure (or certain) she had seen it"; "was very sure in his beliefs"; "sure of her friends")

Sense 3
confident, surefooted, sure-footed -- (not liable to error in judgment or action; "most surefooted of the statesmen who dealt with the depression"- Walter Lippman; "demonstrates a surefooted storytelling talent"- Michiko Kakutani)
       => capable (vs. incapable) -- ((usually followed by `of') having capacity or ability; "capable of winning"; "capable of hard work"; "capable of walking on two feet")