lenient; overly soft; too easygoing
Describes a person, attitude, or judgment that is excessively lenient or forgiving, often with a negative connotation of being too soft.
His grading is overly lenient.
overoptimistic; too hopeful; naively optimistic
Used for expectations, forecasts, or plans that are unrealistically optimistic, often implying a lack of caution.
That sales forecast was overoptimistic.
That teacher is so lenient that you won't get scolded even if you forget your homework.
His outlook is always naively optimistic.
Compound of 大 (おお, 'big, great') and 甘 (あま, 'sweet, lenient'). The combination intensifies the meaning of 甘い in its figurative sense of being overly soft or optimistic.