Antonyms of adj self-confident

1 sense of self-confident

Sense 1
self-assured, self-confident -- (showing poise and confidence in your own worth; "hardly more than a boy but firm-knit and self-confident")

INDIRECT (VIA confident) -> diffident, 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")

Similarity of adj self-confident

1 sense of self-confident

Sense 1
self-assured, self-confident -- (showing poise and confidence in your own worth; "hardly more than a boy but firm-knit and self-confident")
       => 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")