Behind and Subnormal

Behind adjective - Not arriving, occurring, or settled at the due, usual, or proper time.

Subnormal and behind are semantically related In some cases you can use "Subnormal" instead an adjective "Behind".

Subnormal adjective - Of a size that is less than average.

Behind and subnormal are semantically related in backward topic. Sometimes you can use "Behind" instead an adjective "Subnormal", if it concerns topics such as slow in growth, with outdated ideas.